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Jha H, Baveja CP, Kamal V, Agarwal PN, Saxena S, Dhakad MS, Sharma D. Comparative Diagnostic of Cervical Tuberculous Lymphadenitis: PCR is a Fast, Efficient, and Improved Diagnostic Approach. THE CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY = JOURNAL CANADIEN DES MALADIES INFECTIEUSES ET DE LA MICROBIOLOGIE MEDICALE 2023; 2023:3312250. [PMID: 37346247 PMCID: PMC10281827 DOI: 10.1155/2023/3312250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 05/27/2023] [Accepted: 05/30/2023] [Indexed: 06/23/2023]
Abstract
Methods The study included 100 clinically suspected cases of TBLN. Fine needle aspirate (FNA) samples were processed for cytology staining and cultured on LJ & BACTEC 12B media. The biochemical tests were performed to identify the isolates at the species level. Additionally, for PCR, DNA was extracted and used for the diagnosis and identification of mycobacterial species. Results Patients ranged from 2 to 45 years with a mean age of 24.96 ± 9.10 years. Out of 100 patients, 73% had clinical symptoms of weight loss, followed by fever (72%), anorexia (66%), and night sweats (58%). 24% of patients were found to be smear-positive after Ziehl-Neelsen (ZN) staining and statistically highly significant with PCR. On LJ medium 34% and on BACTEC radiometric 45% of samples were smearing positive. Overall, 48% of cases were PCR-positive for TBLN. When compared with culture, the sensitivity and specificity of PCR were 93.75% and 100%, respectively, which are higher than cytology. The true positive predictive value (PPV) and negative predictive value (NPV) were 83.3% and 61.5%, respectively. Conclusion This study suggests that PCR is a rapid, sensitive, and specific tool for correct diagnosis of TBLN cases as compared to staining and culture which lead to the early and proper management of mycobacterial diseases.
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Affiliation(s)
- Himanshu Jha
- Department of Microbiology, Maulana Azad Medical College, New Delhi 110002, India
- Lab Strengthening & Diagnostics, Jhpiego, India
| | | | - Vinay Kamal
- Department of Pathology, Maulana Azad Medical College, New Delhi 110002, India
| | | | - Sonal Saxena
- Department of Microbiology, Maulana Azad Medical College, New Delhi 110002, India
| | - Megh Singh Dhakad
- Department of Microbiology, Maulana Azad Medical College, New Delhi 110002, India
| | - Divakar Sharma
- Department of Microbiology, Lady Hardinge Medical College, New Delhi 110001, India
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Velasco-Arnaiz E, Batllori M, Monsonís M, Valls A, Ríos-Barnes M, Simó-Nebot S, Gamell A, Fortuny C, Tebruegge M, Noguera-Julian A. Host, technical, and environmental factors affecting QuantiFERON-TB Gold In-Tube performance in children below 5 years of age. Sci Rep 2022; 12:19908. [PMID: 36402803 PMCID: PMC9675832 DOI: 10.1038/s41598-022-24433-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 11/15/2022] [Indexed: 11/21/2022] Open
Abstract
Interferon-gamma release assays performance can be impaired by host-related, technical and environmental factors, but data in young children are limited. We performed a cross-sectional study of children < 5 years-of-age at risk of tuberculosis (TB), using QuantiFERON-TB Gold In-Tube (QFT-GIT) assays. The impact of the following was evaluated: (i) host-related [age; hematological parameters; erythrocyte sedimentation rate (ESR); C-reactive protein (CRP); and tobacco smoke exposure (TSE) based on serum cotinine concentrations], (ii) technical (pre-analytical delay) and (iii) environmental factors (annual season; monthly temperatures). Of 204 children, 35 (17.2%) were diagnosed with latent TB infection or TB disease. QFT-GIT results were indeterminate in 14 (6.9%) patients. In multivariate analysis, younger age and higher ESR were associated with lower positive control responses (beta: 0.247, p = 0.002 and - 0.204, p = 0.007, respectively), and increasing age was associated with lower rates of indeterminate QFT-GIT results [OR (95% CI) 0.948 (0.903-0.996) per month, p = 0.035]. In children with positive QFT-GIT results, average monthly temperatures correlated with antigen responses (r = 0.453, p = 0.020); also, antigen responses were lower in winter than in other seasons (p = 0.027). Serum cotinine concentrations determined in a subgroup of patients (n = 41) indicated TSE in 36 (88%), positive control responses being lower in children with TSE (p = 0.034). In children < 5 years-of-age, young age, elevated ESR, temperature, annual season and TSE can affect the performance of QFT-GIT assays.
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Affiliation(s)
- Eneritz Velasco-Arnaiz
- grid.411160.30000 0001 0663 8628Malalties Infeccioses i Resposta Inflamatòria Sistèmica en Pediatria; Servei d’Infectologia Pediàtrica, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Marta Batllori
- grid.411160.30000 0001 0663 8628Laboratori de Bioquímica, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Manuel Monsonís
- grid.411160.30000 0001 0663 8628Servei de Microbiologia. Hospital Sant Joan de Déu, Barcelona, Spain
| | - Anna Valls
- grid.411160.30000 0001 0663 8628Laboratori de Bioquímica, Hospital Sant Joan de Déu, Barcelona, Spain
| | - María Ríos-Barnes
- grid.411160.30000 0001 0663 8628Malalties Infeccioses i Resposta Inflamatòria Sistèmica en Pediatria; Servei d’Infectologia Pediàtrica, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Sílvia Simó-Nebot
- grid.411160.30000 0001 0663 8628Malalties Infeccioses i Resposta Inflamatòria Sistèmica en Pediatria; Servei d’Infectologia Pediàtrica, Institut de Recerca Sant Joan de Déu, Barcelona, Spain ,grid.466571.70000 0004 1756 6246CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Anna Gamell
- grid.411160.30000 0001 0663 8628Malalties Infeccioses i Resposta Inflamatòria Sistèmica en Pediatria; Servei d’Infectologia Pediàtrica, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Clàudia Fortuny
- grid.411160.30000 0001 0663 8628Malalties Infeccioses i Resposta Inflamatòria Sistèmica en Pediatria; Servei d’Infectologia Pediàtrica, Institut de Recerca Sant Joan de Déu, Barcelona, Spain ,grid.466571.70000 0004 1756 6246CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain ,grid.5841.80000 0004 1937 0247Departament de Cirurgia i Especialitats Medicoquirúrgiques, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain ,Translational Research Network in Pediatric Infectious Diseases (RITIP), Madrid, Spain
| | - Marc Tebruegge
- grid.83440.3b0000000121901201Department of Infection, Immunity and Inflammation, UCL Great Ormond Street Institute of Child Health, University College London, London, UK ,grid.1008.90000 0001 2179 088XDepartment of Pediatrics, University of Melbourne, Parkville, Australia ,Department of Paediatrics, Klinik Ottakring, Wiener Gesundheitsverbund, Vienna, Austria
| | - Antoni Noguera-Julian
- grid.411160.30000 0001 0663 8628Malalties Infeccioses i Resposta Inflamatòria Sistèmica en Pediatria; Servei d’Infectologia Pediàtrica, Institut de Recerca Sant Joan de Déu, Barcelona, Spain ,grid.466571.70000 0004 1756 6246CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain ,grid.5841.80000 0004 1937 0247Departament de Cirurgia i Especialitats Medicoquirúrgiques, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain ,Translational Research Network in Pediatric Infectious Diseases (RITIP), Madrid, Spain ,grid.411160.30000 0001 0663 8628Hospital Sant Joan de Déu, Passeig Sant Joan de Déu 2, Esplugues de Llobregat, 08950 Barcelona, Spain
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Lessons Learned from Implementation of an Interferon Gamma Release Assay to Screen for Latent Tuberculosis Infection in a Large Multicenter Observational Cohort Study in Brazil. Microbiol Spectr 2021; 9:e0116321. [PMID: 34851140 PMCID: PMC8635161 DOI: 10.1128/spectrum.01163-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interferon gamma release assay (IGRA) has emerged as a useful tool for identifying latent tuberculosis infection (LTBI). This assay can be performed through testing platforms such as the QuantiFERON-TB Gold Plus (QFT-Plus) assay. This in vitro test has been incorporated into several guidelines worldwide and has recently been considered by the World Health Organization (WHO) for the diagnosis of LTBI. The possibility of systematically implementing IGRAs such as the QFT-Plus assay in centers that perform LTBI screening has been accelerated by the decreased availability of the tuberculin skin test (TST) in several countries. Nevertheless, the process to implement IGRA testing in routine clinical care has many gaps. The study utilized the expertise acquired by the laboratory teams of the Regional Prospective Observational Research in Tuberculosis (RePORT)-Brazil consortium during study protocol implementation of LTBI screening of tuberculosis (TB) close contacts. RePORT-Brazil includes clinical research sites from Brazilian cities and is the largest multicenter cohort of TB close contacts in the country to date. Operational and logistical challenges faced during IGRA implementation in all study laboratories are described, as well as the solutions that were developed and led to the successful establishment of IGRA testing in RePORT-Brazil. The descriptions of the problems identified and resolved in this study can assist laboratories implementing IGRAs, in addition to manufacturers of IGRAs providing effective technical support. This will facilitate the implementation of IGRA testing in countries with large TB burdens, such as Brazil. IMPORTANCE The IGRA has emerged as a useful tool for identifying persons with LTBI. Although the implementation of IGRAs is of utmost importance, to our knowledge there is scarce information on the identification of logistical and technical challenges for systematic screening for LTBI on a large scale. Thus, the descriptions of the problems identified and resolved in this study can assist laboratories implementing IGRAs, in addition to manufacturers of IGRAs providing effective technical support. This will facilitate the implementation of IGRA testing in countries with large TB burdens, such as Brazil.
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Development of a Simple and Robust Whole Blood Assay with Dual Co-Stimulation to Quantify the Release of T-Cellular Signature Cytokines in Response to Aspergillus fumigatus Antigens. J Fungi (Basel) 2021; 7:jof7060462. [PMID: 34201183 PMCID: PMC8230040 DOI: 10.3390/jof7060462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 12/23/2022] Open
Abstract
Deeper understanding of mold-induced cytokine signatures could promote advances in the diagnosis and treatment of invasive mycoses and mold-associated hypersensitivity syndromes. Currently, most T-cellular immunoassays in medical mycology require the isolation of mononuclear cells and have limited robustness and practicability, hampering their broader applicability in clinical practice. Therefore, we developed a simple, cost-efficient whole blood (WB) assay with dual α-CD28 and α-CD49d co-stimulation to quantify cytokine secretion in response to Aspergillus fumigatus antigens. Dual co-stimulation strongly enhanced A. fumigatus-induced release of T-cellular signature cytokines detectable by enzyme-linked immunosorbent assay (ELISA) or a multiplex cytokine assay. Furthermore, T-cell-dependent activation and cytokine response of innate immune cells was captured by the assay. The protocol consistently showed little technical variation and high robustness to pre-analytic delays of up to 8 h. Stimulation with an A. fumigatus lysate elicited at least 7-fold greater median concentrations of key T-helper cell signature cytokines, including IL-17 and the type 2 T-helper cell cytokines IL-4 and IL-5 in WB samples from patients with Aspergillus-associated lung pathologies versus patients with non-mold-related lung diseases, suggesting high discriminatory power of the assay. These results position WB-ELISA with dual co-stimulation as a simple, accurate, and robust immunoassay for translational applications, encouraging further evaluation as a platform to monitor host immunity to opportunistic pathogens.
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Impact of T-Cell Xtend on T-SPOT. TB Assay in High-Risk Individuals after Delayed Blood Sample Processing. J Clin Microbiol 2021; 59:JCM.00120-21. [PMID: 33658266 DOI: 10.1128/jcm.00120-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/23/2021] [Indexed: 11/20/2022] Open
Abstract
T-SPOT.TB (T-SPOT) is an interferon gamma release assay (IGRA) used to detect infection with Mycobacterium tuberculosis based on the number of spot-forming T cells; however, delays in sample processing have been shown to reduce the number of these spots that are detected following laboratory processing. Adding T-Cell Xtend (XT) into blood samples before processing reportedly extends the amount of time allowed between blood collection and processing up to 32 h. In this study, paired blood samples from 306 adolescents and adults at high risk for latent tuberculosis (TB) infection (LTBI) or progression to TB disease were divided into three groups: (i) early processing (∼4.5 h after collection) with and without XT, (ii) delayed processing (∼24 h after collection) with and without XT, and (iii) early processing without XT and delayed processing with XT. The participants' paired samples were processed at a local laboratory and agreement of qualitative and quantitative results was assessed. The addition of XT did not consistently increase or decrease the number of spots. In groups 1, 2, and 3, samples processed with XT had 13% (10/77), 28.0% (30/107), and 24.6% (30/122), respectively, more spots, while 33.8% (26/77), 26.2% (28/107), and 38.5% (47/122) had fewer spots than samples processed without XT. The findings suggest that XT does not reliably mitigate the loss of spot-forming T cells in samples with processing delay.
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Uwamino Y, Sakai A, Nishimura T, Noguchi M, Uno S, Fujiwara H, Mori M, Wakui M, Murata M, Hasegawa N. Effect of refrigeration of blood samples in lithium-heparin tubes on QuantiFERON TB Gold Plus test result. J Infect Chemother 2019; 26:312-314. [PMID: 31836288 DOI: 10.1016/j.jiac.2019.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/30/2019] [Accepted: 10/02/2019] [Indexed: 10/25/2022]
Abstract
The QuantiFERON TB Gold Plus (QFT-Plus) test is a newly approved interferon-gamma releasing assay test for detecting latent tuberculosis. Although blood samples for QFT test can be refrigerated for 48 h in lithium-heparin tubes according to package inserts, no published data are available on the effects of sample refrigeration on the test results. We conducted a clinical study that aimed to elucidate whether sample refrigeration for 48 h affects QFT-Plus test results. We collected 2 blood samples each from 40 participants for QFT-Plus; one sample was refrigerated before incubation for QFT-Plus assay, while the other sample was incubated soon after collection and treated as control. After comparing QFT-Plus test results of refrigerated samples and control samples, the concordance rate and kappa coefficient between them were 95% and 0.90, respectively. Thus, blood samples for QFT-Plus test can be refrigerated for 48 h in lithium-heparin tubes without influencing the test results.
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Affiliation(s)
- Yoshifumi Uwamino
- Department of Laboratory Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan; Department of Infectious Diseases, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Akiko Sakai
- Department of Laboratory Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Tomoyasu Nishimura
- Health Center, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Masayo Noguchi
- Department of Laboratory Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Shunsuke Uno
- Department of Infectious Diseases, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Hiroshi Fujiwara
- Department of Infectious Diseases, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Masaaki Mori
- Health Center, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Masatoshi Wakui
- Department of Laboratory Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Mitsuru Murata
- Department of Laboratory Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
| | - Naoki Hasegawa
- Department of Infectious Diseases, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan.
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7
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Teranishi S, Kobayashi N, Aoki A, Katakura S, Yamamoto M, Koizumi H, Kudo M, Kaneko T. Reproducibility of the T-SPOT.TB test for screening Mycobacterium tuberculosis infection in Japan. J Infect Chemother 2019; 26:194-198. [PMID: 31495568 DOI: 10.1016/j.jiac.2019.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 07/03/2019] [Accepted: 08/09/2019] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The interferon-gamma release assay (IGRA) is useful for diagnosing Mycobacterium tuberculosis infections, especially in countries where Bacille Calmette-Guérin vaccinations are performed. However, reproducibility of the IGRA is unclear, as recent data suggest high IGRA conversion and reversion rates in serial tests among healthcare workers. This longitudinal study aimed to evaluate reproducibility of T-SPOT.TB for screening M. tuberculosis infections in Japan. METHODS Results of T-SPOT.TB tests performed between April 2014 and March 2016 at two hospitals in Yokohama, Japan, where the incidence of tuberculosis was 18.0 per 100,000 population in 2014, were analyzed. RESULTS In total, 3890 T-SPOT.TB tests were included. Overall, positive and negative test rates were 8.4% and 87.6%, respectively. Among 373 serial tests within two years, conversion and reversion rates were only 1.1% and 12.5%, respectively. Almost all patients who were initially negative (98.9%) remained so. There was no statistically significant difference between the outcomes observed at the two hospitals. CONCLUSIONS The conversion rate of T-SPOT.TB in Japan is as low as that recently reported in other countries where the incidence of tuberculosis is low. These data indicate that T-SPOT.TB is a reproducible tuberculosis screening tool at local hospitals in areas with a moderate incidence of tuberculosis.
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Affiliation(s)
- Shuhei Teranishi
- Department of Pulmonology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Nobuaki Kobayashi
- Department of Pulmonology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
| | - Ayako Aoki
- Department of Pulmonology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Seigo Katakura
- Department of Pulmonology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Masaki Yamamoto
- Respiratory Disease Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama 232-0024, Japan
| | - Harumi Koizumi
- Department of Respiratory Medicine, Yokohama Minamikyousai Hospital, 1-21-1 Mutsuurahigashi, Kanazawa-ku, Yokohama, 236-0037, Japan
| | - Makoto Kudo
- Respiratory Disease Center, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami-ku, Yokohama 232-0024, Japan
| | - Takeshi Kaneko
- Department of Pulmonology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
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Agarwal S, Nguyen DT, Lew JD, Graviss EA. Discordance between the QuantiFERON Gold In-Tube and QuantiFERON Gold Plus assays associated with country of birth TB incidence. Tuberculosis (Edinb) 2019; 116S:S2-S10. [PMID: 31060960 DOI: 10.1016/j.tube.2019.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 10/18/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND The new QuantiFERON Gold Plus (QFT+) assay is used for diagnosing tuberculosis (TB) infection and has 2 phlebotomy methods: direct (QFT + D) and single tube transfer (QFT + T). Little data is available on how the TB incidence in the country of birth (COB) of healthcare workers (HCWs) can impact the assay results. METHODS QuantiFERON Gold In-Tube (QFT-G), QFT + D and QFT + T assays were obtained from a single blood draw and compared for HCWs annually tested for TB infection. HCWs COB was ranked as: high (≥150 per 100,000), medium (20-149), and low TB incidence (<20 TB cases). RESULTS In 265 HCWs, QFT-G/+D/+T results from medium TB incidence COB (15.6%, 16.9% and 22.1%) were more likely to be positive than high (9.7%, 11.8% and 16.1%) or low incidence COB (6.3%, 8.4% and 10.5%). Agreement between assay results for high, medium and low TB incidence COB were: 95.7%, 83.1%, and 95.8% between QFT-G/QFT + D (p = 0.003), 91.4%, 88.3% and 95.8% between QFT-G/QFT + T (p = 0.187), and 91.4%, 76.6%, and 91.6% between QFT + D/QFT + T (p = 0.005). CONCLUSION Lower agreement and a higher proportion of positivity were found in QFT-G/+D/+T results in individuals from medium TB incidence COB. QFT + may be more sensitive than QFT-G in HCWs from medium TB incidence COB.
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Affiliation(s)
- Saroochi Agarwal
- Houston Methodist Research Institute, 6670 Bertner Ave, Houston, TX, 77030, USA.
| | - Duc T Nguyen
- Houston Methodist Research Institute, 6670 Bertner Ave, Houston, TX, 77030, USA.
| | - Justin D Lew
- Houston Methodist Research Institute, 6670 Bertner Ave, Houston, TX, 77030, USA.
| | - Edward A Graviss
- Houston Methodist Research Institute, 6670 Bertner Ave, Houston, TX, 77030, USA.
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Meier NR, Volken T, Geiger M, Heininger U, Tebruegge M, Ritz N. Risk Factors for Indeterminate Interferon-Gamma Release Assay for the Diagnosis of Tuberculosis in Children-A Systematic Review and Meta-Analysis. Front Pediatr 2019; 7:208. [PMID: 31192175 PMCID: PMC6548884 DOI: 10.3389/fped.2019.00208] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 05/08/2019] [Indexed: 12/26/2022] Open
Abstract
Background: Interferon-gamma release assays (IGRA) are well-established immunodiagnostic tests for tuberculosis (TB) in adults. In children these tests are associated with higher rates of false-negative and indeterminate results. Age is presumed to be one factor influencing cytokine release and therefore test performance. The aim of this study was to systematically review factors associated with indeterminate IGRA results in pediatric patients. Methods: Systematic literature review guided by the preferred reporting items for systematic reviews and meta-analyses (PRISMA) searching PubMed, EMBASE, and Web of Science. Studies reporting results of at least one commercially available IGRA (QuantiFERON-TB, T-SPOT.TB) in pediatric patient groups were included. Random effects meta-analysis was used to assess proportions of indeterminate IGRA results. Heterogeneity was assessed using the I2 value. Risk differences were calculated for studies comparing QuantiFERON-TB and T-SPOT.TB in the same study. Meta-regression was used to further explore the influence of study level variables on heterogeneity. Results: Of 1,293 articles screened, 133 studies were included in the final analysis. These assessed QuantiFERON-TB only in 77.4% (103/133), QuantiFERON-TB and T-SPOT.TB in 15.8% (21/133), and T-SPOT.TB only in 6.8% (9/133) resulting in 155 datasets including 107,418 participants. Overall 4% of IGRA results were indeterminate, and T-SPOT.TB (0.03, 95% CI 0.02-0.05) and QuantiFERON-TB assays (0.05, 95% CI 0.04-0.06) showed similar proportions of indeterminate results; pooled risk difference was-0.01 (95% CI -0.03 to 0.00). Significant differences with lower proportions of indeterminate assays with T-SPOT.TB compared to QuantiFERON-TB were only seen in subgroup analyses of studies performed in Africa and in non-HIV-infected immunocompromised patients. Meta-regression confirmed lower proportions of indeterminate results for T-SPOT.TB compared to QuantiFERON-TB only among studies that reported results from non-HIV-infected immunocompromised patients (p < 0.001). Conclusion: On average indeterminate IGRA results occur in 1 in 25 tests performed. Overall, there was no difference in the proportion of indeterminate results between both commercial assays. However, our findings suggest that in patients in Africa and/or patients with immunocompromising conditions other than HIV infection the T-SPOT.TB assay appears to produce fewer indeterminate results.
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Affiliation(s)
- Noëmi R Meier
- Mycobacterial Research Laboratory, University of Basel Children's Hospital, Basel, Switzerland.,Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Thomas Volken
- School of Health Professions, Zürich University of Applied Sciences, Winterthur, Switzerland
| | - Marc Geiger
- Faculty of Medicine, University of Basel, Basel, Switzerland
| | - Ulrich Heininger
- Faculty of Medicine, University of Basel, Basel, Switzerland.,Paediatric Infectious Diseases and Vaccinology Unit, University of Basel Children's Hospital, Basel, Switzerland
| | - Marc Tebruegge
- UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom.,Department of Paediatric Infectious Diseases and Immunology, Evelina London Children's Hospital, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom.,Royal Children's Hospital Melbourne, Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Nicole Ritz
- Mycobacterial Research Laboratory, University of Basel Children's Hospital, Basel, Switzerland.,Faculty of Medicine, University of Basel, Basel, Switzerland.,Paediatric Infectious Diseases and Vaccinology Unit, University of Basel Children's Hospital, Basel, Switzerland.,Royal Children's Hospital Melbourne, Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
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10
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Agarwal S, Nguyen DT, Lew JD, Graviss EA. Performance and variability of QuantiFERON Gold Plus assay associated with phlebotomy type. PLoS One 2018; 13:e0207892. [PMID: 30452485 PMCID: PMC6242684 DOI: 10.1371/journal.pone.0207892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/07/2018] [Indexed: 11/25/2022] Open
Abstract
Background QuantiFERON Gold Plus (Plus) assay has two approved methods for blood collection: direct in-tube (Plus direct) or the transfer of blood from a lithium heparin tube (Plus transfer). Currently, there is little data comparing the results of Plus and the QuantiFERON Gold In-Tube (Gold) based on blood collection. Methods In 2017, high risk healthcare workers undergoing annual tuberculosis infection screening at Houston Methodist Hospital, a private hospital in the Texas Medical Center (Houston, TX, U.S.A.) were consented and enrolled in a study comparing the Gold-in-tube (Gold), Plus direct in-tube, and Plus transfer assays. Blood was drawn concurrently for all 3 assays. Results Phlebotomy occurred on 300 consecutive, consented and enrolled participants in the study. The proportion of positive test results for the Gold, Plus direct and Plus transfer assays were 10% (29/300), 12% (35/299) and 17% (51/299), respectively. The agreement in the results of Gold versus Plus direct, Gold versus Plus transfer, and Plus direct versus Plus transfer was 91%, kappa (κ) = 0.56; 91%, κ = 0.59; and 85%, κ = 0.37, respectively. Conclusions Among high risk healthcare workers in a low prevalence tuberculosis setting, the Gold Plus assay had a higher proportion of positive results than the Gold in-tube assay. The agreement between the Gold, Plus direct and Plus transfer assays was unexpectedly low for simultaneously obtained samples. Blood transfer using lithium heparin offers individual clinics and public health programs greater ability to customize protocols, but variability of results still exists.
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Affiliation(s)
- Saroochi Agarwal
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, Texas, United States of America
| | - Duc T Nguyen
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, Texas, United States of America
| | - Justin D Lew
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, Texas, United States of America
| | - Edward A Graviss
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, Texas, United States of America
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11
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Evaluating an Education Program to Reduce Indeterminate QuantiFERON Gold In-Tube Results. Tuberc Res Treat 2018; 2018:7906846. [PMID: 30405911 PMCID: PMC6201483 DOI: 10.1155/2018/7906846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/14/2018] [Accepted: 09/25/2018] [Indexed: 11/24/2022] Open
Abstract
Background The QuantiFERON Gold In-Tube (QFT-G) assay is used to identify individuals with tuberculosis infection and gives quantitative and qualitative results including positive, negative, or indeterminate results (that cannot be interpreted clinically). Several factors, including immunosuppression and preanalytical factors, have been suggested to be significantly associated with indeterminate QFT-G results. An online education program was designed and implemented to reduce the rate of indeterminate QFT-G test results at Houston Methodist Hospital (HMH). Methods Data from patients' electronic medical records having indeterminate QFT-G results between 01/2015 and 05/2016 at HMH in Houston, TX, were administratively extracted for (1) medical unit where QFT-G phlebotomy was performed, (2) demographics, and (3) ICD-9/10 diagnosis codes. Unit nurses identified with high proportions of indeterminate QFT-G results were emailed a link to an online pretest educational program with a QFT-G blood collection and handling presentation, and a posttest assessment. Results Of the 332 nurses emailed, 94 (28.4%) voluntarily completed both tests within the 6-month time allotted. The nurses that completed the education program had a significantly higher posteducation test score than on the pretest (70.2% versus 55.3%, p<0.001, effect size=0.82). Improved posttest score was seen in 67.0% of participants. No reduction in the proportion of indeterminate test results was seen overall at HMH in the 6 months after education. Conclusions A targeted education program was able to successfully increase nurses' knowledge of blood collection and handling procedures for the QFT-G test, but no association was found between the improvement of posttest score and indeterminate QFT-G test results.
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Nemes E, Rozot V, Geldenhuys H, Bilek N, Mabwe S, Abrahams D, Makhethe L, Erasmus M, Keyser A, Toefy A, Cloete Y, Ratangee F, Blauenfeldt T, Ruhwald M, Walzl G, Smith B, Loxton AG, Hanekom WA, Andrews JR, Lempicki MD, Ellis R, Ginsberg AM, Hatherill M, Scriba TJ. Optimization and Interpretation of Serial QuantiFERON Testing to Measure Acquisition of Mycobacterium tuberculosis Infection. Am J Respir Crit Care Med 2017; 196:638-648. [PMID: 28737960 DOI: 10.1164/rccm.201704-0817oc] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Conversion from a negative to positive QuantiFERON-TB test is indicative of Mycobacterium tuberculosis (Mtb) infection, which predisposes individuals to tuberculosis disease. Interpretation of serial tests is confounded by immunological and technical variability. OBJECTIVES To improve the consistency of serial QuantiFERON-TB testing algorithms and provide a data-driven definition of conversion. METHODS Sources of QuantiFERON-TB variability were assessed, and optimal procedures were identified. Distributions of IFN-γ response levels were analyzed in healthy adolescents, Mtb-unexposed control subjects, and patients with pulmonary tuberculosis. MEASUREMENTS AND MAIN RESULTS Individuals with no known Mtb exposure had IFN-γ values less than 0.2 IU/ml. Among individuals with IFN-γ values less than 0.2 IU/ml, 0.2-0.34 IU/ml, 0.35-0.7 IU/ml, and greater than 0.7 IU/ml, tuberculin skin test positivity results were 15%, 53%, 66%, and 91% (P < 0.005), respectively. Together, these findings suggest that values less than 0.2 IU/ml were true negatives. In short-term serial testing, "uncertain" conversions, with at least one value within the uncertainty zone (0.2-0.7 IU/ml), were partly explained by technical assay variability. Individuals who had a change in QuantiFERON-TB IFN-γ values from less than 0.2 to greater than 0.7 IU/ml had 10-fold higher tuberculosis incidence rates than those who maintained values less than 0.2 IU/ml over 2 years (P = 0.0003). By contrast, "uncertain" converters were not at higher risk than nonconverters (P = 0.229). Eighty-seven percent of patients with active tuberculosis had IFN-γ values greater than 0.7 IU/ml, suggesting that these values are consistent with established Mtb infection. CONCLUSIONS Implementation of optimized procedures and a more rigorous QuantiFERON-TB conversion definition (an increase from IFN-γ <0.2 to >0.7 IU/ml) would allow more definitive detection of recent Mtb infection and potentially improve identification of those more likely to develop disease.
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Affiliation(s)
- Elisa Nemes
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Virginie Rozot
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Hennie Geldenhuys
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Nicole Bilek
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Simbarashe Mabwe
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Deborah Abrahams
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Lebohang Makhethe
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Mzwandile Erasmus
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Alana Keyser
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Asma Toefy
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Yolundi Cloete
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Frances Ratangee
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | | | | | - Gerhard Walzl
- 4 South Africa Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Bronwyn Smith
- 4 South Africa Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Andre G Loxton
- 4 South Africa Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Willem A Hanekom
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Jason R Andrews
- 5 Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; and
| | | | | | | | - Mark Hatherill
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Thomas J Scriba
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
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Nemes E, Rozot V, Geldenhuys H, Bilek N, Mabwe S, Abrahams D, Makhethe L, Erasmus M, Keyser A, Toefy A, Cloete Y, Ratangee F, Blauenfeldt T, Ruhwald M, Walzl G, Smith B, Loxton AG, Hanekom WA, Andrews JR, Lempicki MD, Ellis R, Ginsberg AM, Hatherill M, Scriba TJ. Optimization and Interpretation of Serial QuantiFERON Testing to Measure Acquisition of Mycobacterium tuberculosis Infection. Am J Respir Crit Care Med 2017. [PMID: 28737960 DOI: 10.1164/rc-cm.201704-0817oc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
RATIONALE Conversion from a negative to positive QuantiFERON-TB test is indicative of Mycobacterium tuberculosis (Mtb) infection, which predisposes individuals to tuberculosis disease. Interpretation of serial tests is confounded by immunological and technical variability. OBJECTIVES To improve the consistency of serial QuantiFERON-TB testing algorithms and provide a data-driven definition of conversion. METHODS Sources of QuantiFERON-TB variability were assessed, and optimal procedures were identified. Distributions of IFN-γ response levels were analyzed in healthy adolescents, Mtb-unexposed control subjects, and patients with pulmonary tuberculosis. MEASUREMENTS AND MAIN RESULTS Individuals with no known Mtb exposure had IFN-γ values less than 0.2 IU/ml. Among individuals with IFN-γ values less than 0.2 IU/ml, 0.2-0.34 IU/ml, 0.35-0.7 IU/ml, and greater than 0.7 IU/ml, tuberculin skin test positivity results were 15%, 53%, 66%, and 91% (P < 0.005), respectively. Together, these findings suggest that values less than 0.2 IU/ml were true negatives. In short-term serial testing, "uncertain" conversions, with at least one value within the uncertainty zone (0.2-0.7 IU/ml), were partly explained by technical assay variability. Individuals who had a change in QuantiFERON-TB IFN-γ values from less than 0.2 to greater than 0.7 IU/ml had 10-fold higher tuberculosis incidence rates than those who maintained values less than 0.2 IU/ml over 2 years (P = 0.0003). By contrast, "uncertain" converters were not at higher risk than nonconverters (P = 0.229). Eighty-seven percent of patients with active tuberculosis had IFN-γ values greater than 0.7 IU/ml, suggesting that these values are consistent with established Mtb infection. CONCLUSIONS Implementation of optimized procedures and a more rigorous QuantiFERON-TB conversion definition (an increase from IFN-γ <0.2 to >0.7 IU/ml) would allow more definitive detection of recent Mtb infection and potentially improve identification of those more likely to develop disease.
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Affiliation(s)
- Elisa Nemes
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Virginie Rozot
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Hennie Geldenhuys
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Nicole Bilek
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Simbarashe Mabwe
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Deborah Abrahams
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Lebohang Makhethe
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Mzwandile Erasmus
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Alana Keyser
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Asma Toefy
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Yolundi Cloete
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Frances Ratangee
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | | | | | - Gerhard Walzl
- 4 South Africa Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Bronwyn Smith
- 4 South Africa Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Andre G Loxton
- 4 South Africa Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Willem A Hanekom
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Jason R Andrews
- 5 Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California; and
| | | | | | | | - Mark Hatherill
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Thomas J Scriba
- 1 South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Molecular Medicine, and.,2 Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
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Mangan JM, Galindo-Gonzalez S, Irani TA. Development and initial testing of messages to encourage tuberculosis testing and treatment among Bacille Calmette-Guerin (BCG) vaccinated persons. J Immigr Minor Health 2016; 17:79-88. [PMID: 24141428 DOI: 10.1007/s10903-013-9928-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Misperceptions surrounding the Bacille Calmette-Guerin (BCG) vaccine can lead some vaccinated individuals to resist being tested and treated for tuberculosis (TB). Educational messages to best explain the risk of TB to BCG-vaccinated, Hispanic persons were systematically developed and tested. First, TB program staff provided messages they considered effective. These were analyzed and validated by TB experts, and then presented in group interviews initially to foreign-born Hispanic persons with a TB diagnosis, and then persons without a prior TB diagnosis. Based on interviewees' feedback, preferred statements were used to develop one long and three short comprehensive messages. One-on-one interviews were conducted with Hispanic persons to assess the saliency of the comprehensive educational messages. Participants preferred messages that were gain or positively-framed and explained that BCG does not confer lifelong protection against TB. Participants confirmed the messages would likely have a positive impact on patient decisions to undergo TB testing and treatment.
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Affiliation(s)
- Joan M Mangan
- Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, CORP Bldg. 12 Rm 3217.01, MS E10, Atlanta, GA, 30333, USA,
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15
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Serial testing for latent tuberculosis using QuantiFERON-TB Gold In-Tube: A Markov model. Sci Rep 2016; 6:30781. [PMID: 27469388 PMCID: PMC4965809 DOI: 10.1038/srep30781] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/07/2016] [Indexed: 11/08/2022] Open
Abstract
Healthcare workers (HCWs) in low-incidence settings are often serially tested for latent TB infection (LTBI) with the QuantiFERON-TB Gold In-Tube (QFT) assay, which exhibits frequent conversions and reversions. The clinical impact of such variability on serial testing remains unknown. We used a microsimulation Markov model that accounts for major sources of variability to project diagnostic outcomes in a simulated North American HCW cohort. Serial testing using a single QFT with the recommended conversion cutoff (IFN-g > 0.35 IU/mL) resulted in 24.6% (95% uncertainty range, UR: 23.8–25.5) of the entire population testing false-positive over ten years. Raising the cutoff to >1.0 IU/mL or confirming initial positive results with a (presumed independent) second test reduced this false-positive percentage to 2.3% (95%UR: 2.0–2.6%) or 4.1% (95%UR: 3.7–4.5%), but also reduced the proportion of true incident infections detected within the first year of infection from 76.5% (95%UR: 66.3–84.6%) to 54.8% (95%UR: 44.6–64.5%) or 61.5% (95%UR: 51.6–70.9%), respectively. Serial QFT testing of HCWs in North America may result in tremendous over-diagnosis and over-treatment of LTBI, with nearly thirty false-positives for every true infection diagnosed. Using higher cutoffs for conversion or confirmatory tests (for initial positives) can mitigate these effects, but will also diagnose fewer true infections.
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Negative Tuberculin Skin Test and Prediction of Reversion of QuantiFERON Interferon Gamma Release Assay in US Healthcare Workers. Infect Control Hosp Epidemiol 2016; 37:478-82. [DOI: 10.1017/ice.2015.324] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
QuantiFERON tuberculosis tests (QFT) reverted in (612) 77% of 1,094 low-risk healthcare workers (HCW) testing less than 1.16 IU/mL. Of HCW testing greater than 1.1 IU/mL, 33 (59%) of 56 with negative tuberculin skin tests (TST) reverted vs 8 (6%) of 125 with positive TSTs. Retesting low-risk QFT-positive and TST-negative HCW is prudent.Infect. Control Hosp. Epidemiol. 2016;37(4):478–482
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17
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Effects of acute critical illnesses on the performance of interferon-gamma release assay. Sci Rep 2016; 6:19972. [PMID: 26804487 PMCID: PMC4726381 DOI: 10.1038/srep19972] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 12/22/2015] [Indexed: 01/09/2023] Open
Abstract
Performance of interferon-gamma release assays (IGRAs) is influenced by preanalytical, laboratory and host factors. The data regarding how critical illnesses influence IGRA results are limited. This study aimed to investigate IGRA performance among critically ill patients. Patients admitted to intensive care unit (ICU) were prospectively enrolled, and underwent QuantiFERON-TB Gold In-Tube testing on admission and discharge. The associations between patient factors and IGRA results were explored. In total, 118 patients were included. IGRA results on admission were positive, negative and indeterminate for 10(9%), 36(31%) and 72(61%) patients. All indeterminate results were due to a low mitogen response. Indeterminate results were associated with higher disease severity and lower serum albumin levels. Ninety(76%) patients survived to ICU discharge and had repeat IGRA testing 13.3 ± 10.1 days after first ones. Of those, 43(48%) had indeterminate results, and no IGRA conversion or reversion was observed. The majority (35/51, 69%) of ICU survivors with initial indeterminate results still had indeterminates on follow-up testing. Acute critical illnesses exert a significant impact on IGRA performance and a high proportion of indeterminate results was seen in ICU patients. This study highlights limitation of IGRAs in the critically ill and judicious selection of patients to be tested should be considered.
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Interferon Gamma Release Assays for Latent Tuberculosis: What Are the Sources of Variability? J Clin Microbiol 2016; 54:845-50. [PMID: 26763969 DOI: 10.1128/jcm.02803-15] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interferon gamma release assays (IGRAs) are blood-based tests intended for diagnosis of latent tuberculosis infection (LTBI). IGRAs offer logistical advantages and are supposed to offer improved specificity over the tuberculin skin test (TST). However, recent serial testing studies of low-risk individuals have revealed higher false conversion rates with IGRAs than with TST. Reproducibility studies have identified various sources of variability that contribute to nonreproducible results. Sources of variability can be broadly classified as preanalytical, analytical, postanalytical, manufacturing, and immunological. In this minireview, we summarize known sources of variability and their impact on IGRA results. We also provide recommendations on how to minimize sources of IGRA variability.
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King TC, Upfal M, Gottlieb A, Adamo P, Bernacki E, Kadlecek CP, Jones JG, Humphrey-Carothers F, Rielly AF, Drewry P, Murray K, DeWitt M, Matsubara J, O'Dea L, Balser J, Wrighton-Smith P. T-SPOT.TBInterferon-γ Release Assay Performance in Healthcare Worker Screening at Nineteen U.S. Hospitals. Am J Respir Crit Care Med 2015; 192:367-73. [DOI: 10.1164/rccm.201501-0199oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Jarvis J, Gao Y, de Graaf H, Hughes S, Allan RN, Williams A, Marshall B, Elkington P, Faust SN, Tebruegge M. Environmental temperature impacts on the performance of QuantiFERON-TB Gold In-Tube assays. J Infect 2015; 71:276-80. [DOI: 10.1016/j.jinf.2015.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/04/2015] [Indexed: 11/29/2022]
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Monárrez-Espino J, Enciso-Moreno JA, Laflamme L, Serrano CJ. Serial QuantiFERON-TB Gold In-Tube assay and tuberculin skin test to diagnose latent tuberculosis in household Mexican contacts: conversion and reversion rates and associated factors using conventional and borderline zone definitions. Mem Inst Oswaldo Cruz 2015; 109:863-70. [PMID: 25410989 PMCID: PMC4296490 DOI: 10.1590/0074-0276140085] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 08/19/2014] [Indexed: 01/19/2023] Open
Abstract
A cohort of 123 adult contacts was followed for 18‐24 months (86 completed the
follow-up) to compare conversion and reversion rates based on two serial measures of
QuantiFERON (QFT) and tuberculin skin test (TST) (PPD from TUBERSOL, Aventis Pasteur,
Canada) for diagnosing latent tuberculosis (TB) in household contacts of TB patients
using conventional (C) and borderline zone (BZ) definitions. Questionnaires were used
to obtain information regarding TB exposure, TB risk factors and socio-demographic
data. QFT (IU/mL) conversion was defined as <0.35 to ≥0.35 (C) or <0.35 to
>0.70 (BZ) and reversion was defined as ≥0.35 to <0.35 (C) or ≥0.35 to <0.20
(BZ); TST (mm) conversion was defined as <5 to ≥5 (C) or <5 to >10 (BZ) and
reversion was defined as ≥5 to <5 (C). The QFT conversion and reversion rates were
10.5% and 7% with C and 8.1% and 4.7% with the BZ definitions, respectively. The TST
rates were higher compared with QFT, especially with the C definitions (conversion
23.3%, reversion 9.3%). The QFT conversion and reversion rates were higher for TST
≥5; for TST, both rates were lower for QFT <0.35. No risk factors were associated
with the probability of converting or reverting. The inconsistency and apparent
randomness of serial testing is confusing and adds to the limitations of these tests
and definitions to follow-up close TB contacts.
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Affiliation(s)
| | | | - Lucie Laflamme
- Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden
| | - Carmen J Serrano
- Medical Research Unit Zacatecas, Mexican Institute of Social Security, Zacatecas, Mexico
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Abstract
RATIONALE Interferon gamma (IFN-γ) release assays for latent tuberculosis infection result in a larger-than-expected number of conversions and reversions in occupational screening programs, and reproducibility of test results is a concern. OBJECTIVES Knowledge of the relative contribution and extent of the individual sources of variability (immunological, preanalytical, or analytical) could help optimize testing protocols. METHODS We performed a systematic review of studies published by October 2013 on all potential sources of variability of commercial IFN-γ release assays (QuantiFERON-TB Gold In-Tube and T-SPOT.TB). The included studies assessed test variability under identical conditions and under different conditions (the latter both overall and stratified by individual sources of variability). Linear mixed effects models were used to estimate within-subject SD. MEASUREMENTS AND MAIN RESULTS We identified a total of 26 articles, including 7 studies analyzing variability under the same conditions, 10 studies analyzing variability with repeat testing over time under different conditions, and 19 studies reporting individual sources of variability. Most data were on QuantiFERON (only three studies on T-SPOT.TB). A considerable number of conversions and reversions were seen around the manufacturer-recommended cut-point. The estimated range of variability of IFN-γ response in QuantiFERON under identical conditions was ±0.47 IU/ml (coefficient of variation, 13%) and ±0.26 IU/ml (30%) for individuals with an initial IFN-γ response in the borderline range (0.25-0.80 IU/ml). The estimated range of variability in noncontrolled settings was substantially larger (±1.4 IU/ml; 60%). Blood volume inoculated into QuantiFERON tubes and preanalytic delay were identified as key sources of variability. CONCLUSIONS This systematic review shows substantial variability with repeat IFN-γ release assays testing even under identical conditions, suggesting that reversions and conversions around the existing cut-point should be interpreted with caution.
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Andrews JR, Hatherill M, Mahomed H, Hanekom WA, Campo M, Hawn TR, Wood R, Scriba TJ. The dynamics of QuantiFERON-TB gold in-tube conversion and reversion in a cohort of South African adolescents. Am J Respir Crit Care Med 2015; 191:584-91. [PMID: 25562578 PMCID: PMC4384770 DOI: 10.1164/rccm.201409-1704oc] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/29/2014] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Interferon-γ release assays are used to diagnose tuberculosis infection. In developed countries, high rates of reversion following conversion have been described. OBJECTIVES To assess QuantiFERON TB Gold In-Tube test (QFT) conversion and reversion dynamics in a tuberculosis-endemic setting. METHODS Adolescents aged 12-18 years residing near Cape Town were recruited. Tuberculin skin tests (TSTs) and QFTs were performed at baseline and after 2 years of follow up. Half of the participants had TST and QFT performed at additional time points. Participants were observed for incident tuberculosis disease for up to 5 years. MEASUREMENTS AND MAIN RESULTS Among 5,357 participants, 2,751 (51.4%) and 2,987 (55.8%) had positive QFT and TST results, respectively, at baseline. Annualized QFT and TST conversion risks were 14.0 and 13.0%, respectively, and reversion risks were 5.1 and 4.1%, respectively. Concordance was excellent for conversions (κ = 0.74), but poor for reversions (κ = 0.12). Among recent QFT converters, the magnitude of the QFT value was strongly inversely associated with risk of reversion (P < 0.0001). When longitudinal QFT data were analyzed in a cross-sectional manner, the annual risk of infection was 7.3%, whereas inclusion of reversions in the analysis showed that the actual risk of infection was 14.0%. Incident tuberculosis was 8-fold higher among QFT reverters than in participants with all negative QFT results (1.47 vs. 0.18 cases/100 person-years, P = 0.011). CONCLUSIONS In this tuberculosis-endemic setting, annual risk of infection was extremely high, whereas QFT and TST conversion concordance was higher and QFT reversion rates were lower than reported in low-burden settings.
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Affiliation(s)
- Jason R. Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California
| | - Mark Hatherill
- South African Tuberculosis Vaccine Initiative
- Department of Paediatrics and Child Health, Institute of Infectious Disease and Molecular Medicine, and
| | - Hassan Mahomed
- Western Cape Government: Health, Cape Town, South Africa
- Division of Community Health, Stellenbosch University, Stellenbosch, South Africa; and
| | - Willem A. Hanekom
- South African Tuberculosis Vaccine Initiative
- Department of Paediatrics and Child Health, Institute of Infectious Disease and Molecular Medicine, and
| | - Monica Campo
- Department of Medicine, University of Washington, Seattle, Washington
| | - Thomas R. Hawn
- Department of Medicine, University of Washington, Seattle, Washington
| | - Robin Wood
- Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Thomas J. Scriba
- South African Tuberculosis Vaccine Initiative
- Department of Paediatrics and Child Health, Institute of Infectious Disease and Molecular Medicine, and
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Kasempimolporn S, Thaveekarn W, Kerdpanich P, Skulpichetrat U, Saekhow O, Boonchang S, Bharnthong T, Sitprija V. Performance of a rapid strip test for the serologic diagnosis of latent tuberculosis in children. J Clin Diagn Res 2015; 9:DC11-4. [PMID: 25737986 DOI: 10.7860/jcdr/2015/10989.5403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/02/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND The serodiagnostic tests for tuberculosis (TB) present a high variability in terms of sensitivity and specificity. Data on patients with latent TB infection (LTBI) and children in high prevalence settings are still limited. The present study aimed to evaluate an in-house strip test for detection of anti-M. tuberculosis antibodies in TB patients, mostly children aged under 15 y, grouped into four diagnostic categories: active TB, LTBI, healthy TB contacts, and other non-TB diseases. MATERIALS AND METHODS The diagnostic performance of strip test was compared with the tuberculin skin test (TST) and interferon-gamma release assay (IGRA). Sensitivity and specificity were assessed for all three diagnostic tests. The detection accuracy among the tests was calculated by using a receiver operating characteristic analysis. RESULTS TST and IGRA could diagnose the active TB cases correctly (100%). The sensitivity of strip test for active TB was 58.3% and 37.5% for LTBI, while the sensitivities of TST and IGRA for LTBI were 90.3% and 37.5%, respectively. The overall specificities of strip test and IGRA were 91.5% and 95.7%, respectively, which were superior to that of TST (68.1%). CONCLUSION The strip test did not appear to be useful for diagnosis of active TB in comparison with the current diagnostic standard. The assay may be particularly significant in situations where TB is clinically difficult to diagnose like LTBI and could be a meaningful tool in terms of high specificity and simplicity for ruling in pediatric TB in countries with high TB infection rate. Further studies are needed to determine whether strip test can be improved in its sensitivity and should be implemented into routine clinical practice.
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Affiliation(s)
- Songsri Kasempimolporn
- Advisory Scientist, Department of Research and Development, Queen Saovabha Memorial Institute , Thai Red Cross Society, Bangkok, Thailand
| | - Wichit Thaveekarn
- Scientist, Department of Research and Development, Queen Saovabha Memorial Institute , Thai Red Cross Society, Bangkok, Thailand
| | - Phirangkul Kerdpanich
- Associate Professor, Infectious Disease Unit, Department of Pediatrics, Phramongkutklao Hospital , Bangkok, Thailand
| | - Urailak Skulpichetrat
- Pediatric Fellow, Infectious Disease Unit, Department of Pediatrics, Phramongkutklao Hospital , Bangkok, Thailand
| | - Orawan Saekhow
- Senior Scientist, Department of Research and Development, Queen Saovabha Memorial Institute , Thai Red Cross Society, Bangkok, Thailand
| | - Supatsorn Boonchang
- Laboratory Officer, Department of Research and Development, Queen Saovabha Memorial Institute , Thai Red Cross Society, Bangkok, Thailand
| | - Thipchuta Bharnthong
- Former Head, Department of BCG Vaccine Production, Queen Saovabha Memorial Institute , Thai Red Cross Society, Bangkok, Thailand
| | - Visith Sitprija
- Director Professor, Queen Saovabha Memorial Institute , Thai Red Cross Society, Bangkok, Thailand
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IFN-γ release assay conversions and reversions. Challenges with serial testing in U.S. health care workers. Ann Am Thorac Soc 2014; 11:296-302. [PMID: 24446969 DOI: 10.1513/annalsats.201310-378oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RATIONALE IFN-γ release assays (IGRAs) including the QuantiFERON-TB gold in-tube test (QFT-GIT) are increasingly used in place of the tuberculin skin test (TST) in surveillance programs for Mycobacterium tuberculosis infection in the United States. However, data on conversions, reversions, and predictive value of QFT in such programs for health care workers (HCWs) are limited. OBJECTIVES The purpose of this study is to assess long-term reproducibility and conversion and reversion rates of QFT-GIT among HCWs who underwent serial testing at a tertiary care center in the United States. METHODS Retrospective chart review of HCWs at the Central Arkansas Veterans Healthcare System (CAVHS) who underwent serial testing with QFT-GIT as a part of their employee screening between November 1, 2008 and January 31, 2011. MEASUREMENTS AND MAIN RESULTS A total of 2,303 HCWs had at least 2 QFT-GITs 1 year apart. The initial QFT-GIT was positive for 69 and 2 were indeterminate. Of these 69 HCWs, 31 (45%) reverted on repeat testing, and 25 of 31 (80.6%) HCWs who reverted had a negative look-back TST. Of the 2,232 HCWs with an initial negative QFT-GIT, 71 (3.2%) converted on repeat testing. A third QFT-GIT assay was performed in 41 of the 71 converters and 90% (37 of 41) reverted back to negative. Only two HCWs had TST and QFT-GIT conversion. CONCLUSIONS Poor IGRA reproducibility and a low predictive value of QFT-GIT conversions indicate that QFT-GIT with current interpretation criteria should not be used for serial screening of U.S. HCWs. Negative TSTs have higher reproducibility than QFT-GIT for serial testing of HCWs in low tuberculosis incidence settings.
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Schmidt T, Schub D, Wolf M, Dirks J, Ritter M, Leyking S, Singh M, Zawada AM, Blaes-Eise AB, Samuel U, Sester U, Sester M. Comparative analysis of assays for detection of cell-mediated immunity toward cytomegalovirus and M. tuberculosis in samples from deceased organ donors. Am J Transplant 2014; 14:2159-67. [PMID: 25040687 DOI: 10.1111/ajt.12787] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/07/2014] [Accepted: 04/16/2014] [Indexed: 01/25/2023]
Abstract
Cell-mediated immunity assays could be valuable for risk assessment of organ donors, but no data exist on their feasibility in deceased donors. In this study, 105 deceased donors (52.3 ± 16.9 years) were screened at the time of organ procurement. Pathogen-specific stimulation was performed using a cytomegalovirus (CMV) lysate, tuberculin (purified protein derivative [PPD]) and soluble Mycobacterium tuberculosis-specific ESAT-6/CFP-10 proteins in combination with an in-house fluorescence-activated cell sorting (FACS) assay or commercial assay formats (QuantiFERON-CMV/TB for ELISA, T-SPOT.TB for ELISPOT). CMV-IgG antibody titers were determined as gold standard for CMV infection; 51.4% of samples were CMV seropositive. Indeterminate results were observed in 47.6% of ELISA, 12.5% of FACS and 0% of ELISPOT assays. Agreement with serology was highest for FACS (95.6%, κ = 0.91), followed by ELISPOT (84.0%, κ = 0.68) and ELISA (80.0%, κ = 0.60). Agreement between ELISA and serology increased if the CMV lysate was used as stimulus (96.7%, κ = 0.92). Among the T cell assays, agreement between ELISPOT and FACS was highest (κ = 0.70). PPD-positive results among valid samples differed between assays (26.5% for ELISA, 23.1% for FACS and 50.5% for ELISPOT); 2.0% were QuantiFERON-TB positive, 3.3% were ESAT-6/CFP-10-positive in FACS and 13.4% were positive in the T-SPOT.TB assay. In conclusion, cellular immunity may be analyzed from samples of deceased donors, although the assays differ in the rate of positivity and indeterminate results.
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Affiliation(s)
- T Schmidt
- Department of Transplant and Infection Immunology, Saarland University, Homburg, Germany
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Gamma interferon release assays for detection of Mycobacterium tuberculosis infection. Clin Microbiol Rev 2014; 27:3-20. [PMID: 24396134 DOI: 10.1128/cmr.00034-13] [Citation(s) in RCA: 553] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Identification and treatment of latent tuberculosis infection (LTBI) can substantially reduce the risk of developing active disease. However, there is no diagnostic gold standard for LTBI. Two tests are available for identification of LTBI: the tuberculin skin test (TST) and the gamma interferon (IFN-γ) release assay (IGRA). Evidence suggests that both TST and IGRA are acceptable but imperfect tests. They represent indirect markers of Mycobacterium tuberculosis exposure and indicate a cellular immune response to M. tuberculosis. Neither test can accurately differentiate between LTBI and active TB, distinguish reactivation from reinfection, or resolve the various stages within the spectrum of M. tuberculosis infection. Both TST and IGRA have reduced sensitivity in immunocompromised patients and have low predictive value for progression to active TB. To maximize the positive predictive value of existing tests, LTBI screening should be reserved for those who are at sufficiently high risk of progressing to disease. Such high-risk individuals may be identifiable by using multivariable risk prediction models that incorporate test results with risk factors and using serial testing to resolve underlying phenotypes. In the longer term, basic research is necessary to identify highly predictive biomarkers.
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28
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Pai M, Banaei N. Occupational screening of health care workers for tuberculosis infection: tuberculin skin testing or interferon-γ release assays? Occup Med (Lond) 2014; 63:458-60. [PMID: 24097956 DOI: 10.1093/occmed/kqt105] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Madhukar Pai
- McGill International TB Centre & Department of Epidemiology & Biostatistics, McGill University, Montreal, Quebec, Canada
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29
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Dorman SE, Belknap R, Graviss EA, Reves R, Schluger N, Weinfurter P, Wang Y, Cronin W, Hirsch-Moverman Y, Teeter LD, Parker M, Garrett DO, Daley CL. Interferon-γ release assays and tuberculin skin testing for diagnosis of latent tuberculosis infection in healthcare workers in the United States. Am J Respir Crit Care Med 2014; 189:77-87. [PMID: 24299555 DOI: 10.1164/rccm.201302-0365oc] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE IFN-γ release assays (IGRAs) are alternatives to tuberculin skin testing (TST) for diagnosis of latent tuberculosis infection. Limited data suggest IGRAs may not perform well for serial testing of healthcare workers (HCWs). OBJECTIVES Determine the performance characteristics of IGRAs versus TST for serial testing of HCWs. METHODS A longitudinal study involving 2,563 HCWs undergoing occupational tuberculosis screening at four healthcare institutions in the United States, where the average tuberculosis case rate ranged from 4 to 9 per 100,000 persons. QuantiFERON-TB Gold In-Tube (QFT-GIT), T-SPOT.TB (T-SPOT), and TST were performed at baseline and every 6 months for 18 months between February 2008 and March 2011. MEASUREMENTS AND MAIN RESULTS A total of 2,418 HCWs completed baseline testing, which was positive for 125 (5.2%) by TST, 118 (4.9%) by QFT-GIT, and 144 (6.0%) by T-SPOT. A baseline positive TST with negative IGRAs was associated with bacillus Calmette-Guérin (BCG) vaccination (odds ratio: 25.1 [95% confidence interval: 15.5, 40.5] vs. no BCG). Proportions of participants with test conversion during the study period were 138 of 2,263 (6.1%) for QFT-GIT, 177 of 2,137 (8.3%) for T-SPOT, and 21 of 2,293 (0.9%) for TST (P < 0.001 for QFT-GIT vs. TST and for T-SPOT vs. TST; P = 0.005 for QFT-GIT vs. T-SPOT). Of the QFT-GIT and T-SPOT converters, 81 of 106 (76.4%) and 91 of 118 (77.1%), respectively, were negative when retested 6 months later. There was negative/positive discordance for 15 of 170 (8.8%) participants by QFT-GIT and for 19 of 151 (12.6%) by T-SPOT when blood was drawn 2 weeks later. CONCLUSIONS Most conversions among HCWs in low TB incidence settings appear to be false positives, and these occurred six to nine times more frequently with IGRAs than TST; repeat testing of apparent converters is warranted.
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Affiliation(s)
- Susan E Dorman
- 1 Johns Hopkins University School of Medicine, Baltimore, Maryland
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30
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Whitworth WC, Goodwin DJ, Racster L, West KB, Chuke SO, Daniels LJ, Campbell BH, Bohanon J, Jaffar AT, Drane W, Sjoberg PA, Mazurek GH. Variability of the QuantiFERON®-TB gold in-tube test using automated and manual methods. PLoS One 2014; 9:e86721. [PMID: 24466211 PMCID: PMC3900587 DOI: 10.1371/journal.pone.0086721] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/13/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The QuantiFERON®-TB Gold In-Tube test (QFT-GIT) detects Mycobacterium tuberculosis (Mtb) infection by measuring release of interferon gamma (IFN-γ) when T-cells (in heparinized whole blood) are stimulated with specific Mtb antigens. The amount of IFN-γ is determined by enzyme-linked immunosorbent assay (ELISA). Automation of the ELISA method may reduce variability. To assess the impact of ELISA automation, we compared QFT-GIT results and variability when ELISAs were performed manually and with automation. METHODS Blood was collected into two sets of QFT-GIT tubes and processed at the same time. For each set, IFN-γ was measured in automated and manual ELISAs. Variability in interpretations and IFN-γ measurements was assessed between automated (A1 vs. A2) and manual (M1 vs. M2) ELISAs. Variability in IFN-γ measurements was also assessed on separate groups stratified by the mean of the four ELISAs. RESULTS Subjects (N = 146) had two automated and two manual ELISAs completed. Overall, interpretations were discordant for 16 (11%) subjects. Excluding one subject with indeterminate results, 7 (4.8%) subjects had discordant automated interpretations and 10 (6.9%) subjects had discordant manual interpretations (p = 0.17). Quantitative variability was not uniform; within-subject variability was greater with higher IFN-γ measurements and with manual ELISAs. For subjects with mean TB Responses ±0.25 IU/mL of the 0.35 IU/mL cutoff, the within-subject standard deviation for two manual tests was 0.27 (CI95 = 0.22-0.37) IU/mL vs. 0.09 (CI95 = 0.07-0.12) IU/mL for two automated tests. CONCLUSION QFT-GIT ELISA automation may reduce variability near the test cutoff. Methodological differences should be considered when interpreting and using IFN-γ release assays (IGRAs).
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Affiliation(s)
- William C. Whitworth
- Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail:
| | - Donald J. Goodwin
- Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America
| | - Laura Racster
- Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America
| | - Kevin B. West
- Department of Occupational Medicine/TB Prevention/Deployment Medicine, Wilford Hall Medical Center, Reid Clinic, Lackland Air Force Base, Texas, United States of America
| | - Stella O. Chuke
- Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Northrop Grumman Information Systems Sector, Atlanta, Georgia, United States of America
| | - Laura J. Daniels
- Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- CDC Foundation, Atlanta, Georgia, United States of America
| | - Brandon H. Campbell
- Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Northrop Grumman Information Systems Sector, Atlanta, Georgia, United States of America
| | - Jamaria Bohanon
- Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America
- CDC Foundation, Atlanta, Georgia, United States of America
| | - Atheer T. Jaffar
- Epidemiology Services Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, United States of America
- CDC Foundation, Atlanta, Georgia, United States of America
| | - Wanzer Drane
- Professor Emeritus of Biostatistics, University of South Carolina, Columbia, South Carolina, United States of America
| | - Paul A. Sjoberg
- Epidemiology Consult Services, United States Air Force School of Aerospace Medicine, Wright-Patterson Air Force Base, Dayton, Ohio, United States of America
| | - Gerald H. Mazurek
- Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
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Slater ML, Welland G, Pai M, Parsonnet J, Banaei N. Challenges with QuantiFERON-TB Gold assay for large-scale, routine screening of U.S. healthcare workers. Am J Respir Crit Care Med 2013; 188:1005-10. [PMID: 23978270 DOI: 10.1164/rccm.201305-0831oc] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE North American occupational health programs that switched from the tuberculin skin test (TST) to IFN-γ release assays for latent tuberculosis screening are reporting challenges with interpretation of serial testing results in healthcare workers (HCWs). However, limited data exist on the reproducibility of serial IFN-γ release assay results in low-risk HCWs. OBJECTIVES To evaluate the short-term reproducibility of QuantiFERON-TB Gold In-Tube (QFT) in a large cohort of HCWs and to define a QFT cutoff yielding a conversion rate equivalent to historical TST rates. METHODS We retrospectively evaluated the QFT results from HCWs with two or more QFT tests performed between June 2008 and July 2010 at an academic institution. Outcome measures were proportions of reproducibility, quantitative results, and conversion rates with alternate QFT cutoffs. MEASUREMENTS AND MAIN RESULTS A total of 9,153 HCWs with two or more QFT tests were included in the analysis. Of 8,227 individuals with a negative result, 4.4% (n = 361) converted their QFT result over 2 years. A total of 261 (72.3%) of the HCWs with conversions underwent repeat short-term testing after the first positive result with 64.8% reverting (n = 169). An IFN-γ cutoff of 5.3 IU/ml or higher (manufacturer's cutoff is ≥0.35 IU/ml) yielded a conversion rate of 0.4%, equal to our institution's historical TST conversion rate. CONCLUSIONS The manufacturer's definition of QFT conversion results in an inflated conversion rate that is incompatible with our low-risk setting. A significantly higher QFT cutoff value is needed to match the historical TST conversion rate. Nonreproducible conversions in most converters suggested false-positive results.
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Weakly positive tests and chronologic variation of the QuantiFERON assay: A retrospective appraisal of usefulness. Tuberculosis (Edinb) 2013; 93:647-53. [DOI: 10.1016/j.tube.2013.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 06/26/2013] [Accepted: 07/30/2013] [Indexed: 11/15/2022]
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Impact of blood volume, tube shaking, and incubation time on reproducibility of QuantiFERON-TB gold in-tube assay. J Clin Microbiol 2013; 51:3521-6. [PMID: 23966505 DOI: 10.1128/jcm.01627-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gamma interferon (IFN-γ) release assays (IGRAs) are functional assays used serially to measure the efficacy of novel tuberculosis (TB) vaccines and to screen health care workers for latent tuberculosis infection (LTBI). However, studies have shown nonreproducible IGRA results. In this study, we investigated the effects of blood volume (0.8, 1.0, and 1.2 ml), tube shaking (gentle versus vigorous), and incubation duration (16, 20, and 24 h) on the reproducibility of QuantiFERON-TB Gold In-Tube (QFT-GIT) results for 50 subjects (33 uninfected and 17 infected). The median IFN-γ TB response (TB antigen [Ag] minus nil value) was significantly higher with 0.8 ml blood (1.04 IU/ml) than with 1.0 ml (0.85 IU/ml; P = 0.002) or 1.2 ml (0.49 IU/ml; P < 0.001) for subjects with LTBI. Compared with 0.8 ml (11.8%), there were larger proportions of false-negative results with 1.0 ml (29.4%; P = 0.2) and 1.2 ml (41.2%; P = 0.05) of blood for infected subjects. Blood volume did not significantly change the proportions of positive results in uninfected controls. Compared with gentle shaking, vigorous shaking increased the median IFN-γ response in nil (0.04 versus 0.06 IU/ml; P < 0.001) and TB Ag (0.12 versus 0.24 IU/ml; P = 0.004) tubes and increased TB responses (TB Agvigorous minus nilgentle) (0.02 versus 0.08 IU/ml; P = 0.004). The duration of incubation did not have a significant impact on the proportion of positive results in uninfected or infected subjects. This study identified blood volume and tube shaking as novel preanalytical sources of variability which require further standardization in order to improve the quality and reproducibility of QFT-GIT results.
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Effect of prolonged incubation time on results of the QuantiFERON TB gold in-tube assay for diagnosis of latent tuberculosis infection. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1377-80. [PMID: 23825190 DOI: 10.1128/cvi.00290-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous reports have shown that the sensitivity of the 6-day lymphocyte stimulation test is much higher than those of commercially available gamma interferon release assays (IGRAs). The aim of this study was to elucidate the effect of prolonged incubation on the results of the QuantiFERON TB Gold in-tube (QFT-GIT) assay. Patients aged >20 years with suspected tuberculosis (TB) were recruited prospectively from 1 May 2009 to 31 December 2010. In addition, healthy volunteers with no history of TB treatment were included as controls. For each participant, three sets of the QFT-GIT assay were performed using 24-, 48-, and 72-h incubation tests, and the results were compared. Thirty-seven patients with suspected pulmonary TB and 33 healthy controls were enrolled in the study. Of the 37 patients with suspected TB, the QFT-GIT assay results were positive for 28 (75.7%) after a 24-h incubation period. After prolonged incubation, the results differed in four (10.8%) of the 37 patients suspected of having TB. Among 27 patients with culture-confirmed TB, the sensitivities of the QFT-GIT assay after the 24-, 48-, and 72-h incubation tests were 85.2%, 81.5%, and 81.5%, respectively. Among the 33 healthy controls, the QFT-GIT assay results were positive in two (6.1%) after a 24-h incubation period. The results changed for two (6.1%) of the 33 healthy controls after prolonged incubation. The specificities of the QFT-GIT assay after 24, 48, and 72 h of incubation were 93.9%, 87.9%, and 90.9%, respectively. Prolonging the incubation time did not increase the sensitivity of the QFT-GIT assay. The manufacturer-recommended incubation time of 16 to 24 h should be respected because prolonged incubation can cause indeterminate or false-positive results.
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Watanabe D, Otani N, Suzuki S, Dohi H, Hirota K, Yonemoto H, Koizumi Y, Otera H, Yajima K, Nishida Y, Uehira T, Shima M, Shirasaka T, Okuno T. Evaluation of VZV-specific cell-mediated immunity in adults infected with HIV-1 by using a simple IFN-γ release assay. J Med Virol 2013; 85:1313-20. [DOI: 10.1002/jmv.23611] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Dai Watanabe
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Naruhito Otani
- Department of Public Health; Hyogo College of Medicine; Osaka Japan
| | - Sachiko Suzuki
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Hiromi Dohi
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Kazuyuki Hirota
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Hitoshi Yonemoto
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Yusuke Koizumi
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Hiroshi Otera
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Keishiro Yajima
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Yasuharu Nishida
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Tomoko Uehira
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Masayuki Shima
- Department of Public Health; Hyogo College of Medicine; Osaka Japan
| | - Takuma Shirasaka
- AIDS Medical Center; National Hospital Organization Osaka National Hospital; Osaka Japan
| | - Toshiomi Okuno
- Department of Microbiology; Hyogo College of Medicine; Osaka Japan
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Zwerling A, Joshi R, Kalantri SP, Dakshinamoorthy G, Reddy MV, Benedetti A, Schwartzman K, Menzies D, Pai M. Trajectories of tuberculosis-specific interferon-gamma release assay responses among medical and nursing students in rural India. J Epidemiol Glob Health 2013; 3:105-17. [PMID: 23856572 PMCID: PMC7320393 DOI: 10.1016/j.jegh.2013.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 03/07/2013] [Accepted: 03/12/2013] [Indexed: 11/29/2022] Open
Abstract
Background: Interferon gamma release assays (IGRAs) have been shown to be highly dynamic tests when used in serial testing for TB infection. However, there is little information demonstrating a clear association between TB exposure and IGRA responses over time, particularly in high TB incidence settings. Objectives: To assess whether QuantiFERON-TB Gold In-Tube (QFT) responses are associated with occupational TB exposures in a cohort of young health care trainees in India. Methods: All medical and nursing students at Mahatma Gandhi Institute of Medical Sciences were approached. Participants were followed up for 18 months; QFT was performed 4 times, once every 6 months. Various modeling approaches were used to define IFN-gamma trajectories and correlations with TB exposure. Results: Among 270 medical and nursing trainees, high rates of conversions (6.3–20.9%) and reversions (20.0–26.2%) were found depending on the definitions used. Stable converters were more likely to have had TB exposure in hospital pre-study. Recent occupational exposures were not consistently associated with QFT responses over time. Conclusion: IFN-gamma responses and rates of change could not be explained by occupational exposure investigated. High conversion and subsequent reversion rates suggest many health care workers (HCWs) would revert in the absence of treatment, either by clearing the infection naturally or due to fluctuations in the underlying immunological response and/or poor assay reproducibility. QFT may not be an ideal diagnostic test for repeated screening of HCWs in a high TB incidence setting.
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Affiliation(s)
- Alice Zwerling
- Department of Epidemiology and Biostatistics, McGill University, Montreal, Canada
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Park JS, Lee JS, Kim MY, Lee CH, Yoon HI, Lee SM, Yoo CG, Kim YW, Han SK, Yim JJ. Monthly follow-ups of interferon-γ release assays among health-care workers in contact with patients with TB. Chest 2013; 142:1461-1468. [PMID: 22556318 DOI: 10.1378/chest.11-3299] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Interferon-γ (IFN-γ) release assays (IGRAs), which can overcome several limitations of the tuberculin skin test in detecting latent TB infection, were introduced recently in routine clinical practice. However, IGRAs are highly dynamic tests, and the T-cell responses tend to fluctuate over time. We wanted to evaluate the conversion and reversion rates of monthly IGRAs over 1 year among health-care workers (HCWs) in contact with patients with TB in South Korea, a country with an intermediate TB burden. METHODS Forty-nine HCWs in contact with patients with active pulmonary TB were prospectively enrolled. Interviews on exposure to patients with active TB, a physical examination, and a QuantiFERON TB Gold In-Tube assay (QFT-GIT) were carried out monthly for 1 year. RESULTS Among 48 participants, 25 (52%) showed inconsistent results in serial testing. When an increase from< 0.35 IU/mL to ≥ 0.70 IU/mL was applied as the definition of a conversion, inconsistent IGRA results were identified in 13 participants (27.0%). Consistency in QFT-GIT results was associated with age, length of service, and baseline IFN-γ levels, but not with the profession of the participant, degree of TB exposure, or wearing of an N95 mask. In five participants, fluctuations in IFN-γ levels showed levels > 0.70 IU/mL two or more times. CONCLUSIONS Fluctuation in IGRA findings was common when HCWs in contact with patients with TB were tested monthly. This could be a result of poor reproducibility of the assay, repeated infection and true reversion, or periodic secretion of antigens from Mycobacterium tuberculosis. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT01121068; URL: www.clinicaltrials.gov
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Affiliation(s)
- Jong Sun Park
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul, South Korea
| | - Ji Sun Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Min Young Kim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Chang Hoon Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, South Korea
| | - Ho Il Yoon
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul, South Korea
| | - Sang-Min Lee
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Chul-Gyu Yoo
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Young Whan Kim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Sung Koo Han
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Jae-Joon Yim
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Lung Institute of Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea.
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Performance of tuberculin skin test compared to QFT-IT to detect latent TB among high-risk contacts in Mexico. Arch Med Res 2013; 44:242-8. [PMID: 23506719 DOI: 10.1016/j.arcmed.2013.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 02/19/2013] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND AIMS We undertook this study to compare the performance of tuberculin skin test (TST) and QuantiFERON-TB-Gold In-tube assay (QFT-IT) to identify latent TB infection (LTBI) among close contacts of pulmonary TB cases. METHODS A cross-sectional study was conducted in north central Mexico. Thirty nine TB index cases diagnosed between 2008 and 2010 and 123 corresponding close contacts were interviewed regarding their exposure time to the index case prior to TB diagnosis and relevant sociodemographic factors. TST (induration ≥5 and ≥10 mm) and QFT-IT (≥0.35 IU/mL) were tested to determine LTBI status. Kappa coefficients were used to assess the agreement between TST and QFT-IT. Multivariate logistic regression modeling using TST and QFT-IT as dependent variables, and cumulative exposure time and sociodemographic variables associated with LTBI were used as independent variables. RESULTS LTBI prevalence in adult contacts was 53.6 and 34.1% when TST cut-offs were set at ≥5 mm and ≥10, respectively, and 41.4% according to QFT-IT. Agreement between TST and QFT-IT was 73.1 and 74.8%, and kappa coefficients 0.47 and 0.46, for TST ≥5 and ≥10 mm, respectively, although these were higher when data were stratified by cumulative exposure, reaching 84.9% and 0.70 for TST ≥5 mm if exposure was ≥500 h/month. None of the predictive variables analyzed for LTBI using multivariate regression was significantly associated. CONCLUSIONS TST ≥5 mm appears to be a useful test to identify LTBI among closely exposed contacts in this geographic setting.
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Trajman A, Steffen RE, Menzies D. Interferon-Gamma Release Assays versus Tuberculin Skin Testing for the Diagnosis of Latent Tuberculosis Infection: An Overview of the Evidence. Pulm Med 2013; 2013:601737. [PMID: 23476763 PMCID: PMC3582085 DOI: 10.1155/2013/601737] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/10/2013] [Indexed: 11/18/2022] Open
Abstract
A profusion of articles have been published on the accuracy and uses of interferon-gamma releasing assays. Here we review the clinical applications, advantages, and limitations of the tuberculin skin test and interferon-gamma release assays and provide an overview of the most recent systematic reviews conducted for different indications for the use of these tests. We conclude that both tests are accurate to detect latent tuberculosis, although interferon-gamma release assays have higher specificity than tuberculin skin testing in BCG-vaccinated populations, particularly if BCG is received after infancy. However, both tests perform poorly to predict risk for progression to active tuberculosis. Interferon-gamma release assays have significant limitations in serial testing because of spontaneous variability and lack of a validated definition of conversion and reversion, making it difficult for clinicians to interpret changes in category (conversions and reversions). So far, the most important clinical evidence, that is, that isoniazid preventive therapy reduces the risk for progression to disease, has been produced only in tuberculin skin test-positive individuals.
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Affiliation(s)
- A. Trajman
- Gama Filho University, 20740-900 Rio de Janeiro, RJ, Brazil
- Montreal Chest Institute, McGill University, Montreal, QC, Canada H2X 2P4
| | - R. E. Steffen
- Federal University of Rio de Janeiro, 21941-913 Rio de Janeiro, RJ, Brazil
| | - D. Menzies
- Montreal Chest Institute, McGill University, Montreal, QC, Canada H2X 2P4
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Zwerling A, Benedetti A, Cojocariu M, McIntosh F, Pietrangelo F, Behr MA, Schwartzman K, Menzies D, Pai M. Repeat IGRA testing in Canadian health workers: conversions or unexplained variability? PLoS One 2013; 8:e54748. [PMID: 23382955 PMCID: PMC3561382 DOI: 10.1371/journal.pone.0054748] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 12/14/2012] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Although North American hospitals are switching from tuberculin testing (TST) to interferon-gamma release assays (IGRAs), data are limited on the association between occupational exposure and serial QuantiFERON-TB Gold In-Tube (QFT) results in healthcare workers (HCWs). METHODS In a cohort of Canadian HCWs, TST and QFT were performed at study enrolment (TST1 and QFT1) and 1 year later (TST2 and QFT2). Conversion and reversion rates were estimated, and correlation with TB exposure was assessed. RESULTS Among 258 HCWs, median age was 36.8 years, 188/258 (73%) were female and 183/258 (71%) were Canadian-born. In 245 subjects with a negative QFT1 we found a QFT conversion rate of 5.3% (13/245, 95% CI 2.9-8.9%). Using more stringent definitions, QFT conversion rates ranged from 2.0 to 5.3%. No TST conversions were found among the 241 HCWs with negative TST1, and no measure of recent TB exposure was associated with QFT conversions. In the 13 HCWs with a positive QFT1, 62% reverted. CONCLUSION Using the conventional QFT conversion definition, we found a higher than expected rate of conversion. Recent occupational exposures were not associated with QFT conversions, and no TST conversions occurred in this cohort, suggesting the 'conversions' may not reflect new TB infection.
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Affiliation(s)
- Alice Zwerling
- Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, Canada
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
| | - Andrea Benedetti
- Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, Canada
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
- Department of Medicine, McGill University Health Centre, Montreal, Canada
| | - Mihaela Cojocariu
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
- Research Institute of the McGill University Health Center, Montreal, Canada
| | - Fiona McIntosh
- Research Institute of the McGill University Health Center, Montreal, Canada
| | - Filomena Pietrangelo
- Department of Occupational Health & Safety, McGill University Health Center, Montreal, Canada
| | - Marcel A. Behr
- Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, Canada
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
- Department of Medicine, McGill University Health Centre, Montreal, Canada
| | - Kevin Schwartzman
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
- Department of Medicine, McGill University Health Centre, Montreal, Canada
| | - Dick Menzies
- Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, Canada
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
- Department of Medicine, McGill University Health Centre, Montreal, Canada
| | - Madhukar Pai
- Department of Epidemiology, Biostatistics & Occupational Health, McGill University, Montreal, Canada
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
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Determining Mycobacterium tuberculosis infection among BCG-immunised Ugandan children by T-SPOT.TB and tuberculin skin testing. PLoS One 2012; 7:e47340. [PMID: 23077594 PMCID: PMC3471887 DOI: 10.1371/journal.pone.0047340] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/10/2012] [Indexed: 12/27/2022] Open
Abstract
Background Children with latent tuberculosis infection (LTBI) represent a huge reservoir for future disease. We wished to determine Mycobacterium tuberculosis (M.tb) infection prevalence among BCG-immunised five-year-old children in Entebbe, Uganda, but there are limited data on the performance of immunoassays for diagnosis of tuberculosis infection in children in endemic settings. We therefore evaluated agreement between a commercial interferon gamma release assay (T-SPOT.TB) and the tuberculin skin test (TST; 2 units RT-23 tuberculin; positive defined as diameter ≥10 mm), along with the reproducibility of T-SPOT.TB on short-term follow-up, in this population. Methodology/Principal Findings We recruited 907 children of which 56 were household contacts of TB patients. They were tested with T-SPOT.TB at age five years and then re-examined with T-SPOT.TB (n = 405) and TST (n = 319) approximately three weeks later. The principal outcome measures were T-SPOT.TB and TST positivity. At five years, 88 (9.7%) children tested positive by T-SPOT.TB. More than half of those that were T-SPOT.TB positive at five years were negative at follow-up, whereas 96% of baseline negatives were consistently negative. We observed somewhat better agreement between initial and follow-up T-SPOT.TB results among household TB contacts (κ = 0.77) than among non-contacts (κ = 0.39). Agreement between T-SPOT.TB and TST was weak (κ = 0.28 and κ = 0.40 for T-SPOT.TB at 5 years and follow-up, respectively). Of 28 children who were positive on both T-SPOT.TB tests, 14 (50%) had a negative TST. Analysis of spot counts showed high levels of instability in responses between baseline and follow-up, indicating variability in circulating numbers of T cells specific for certain M.tb antigens. Conclusions/Significance We found that T-SPOT.TB positives are unstable over a three-week follow-up interval, and that TST compares poorly with T-SPOT.TB, making the categorisation of children as TB-infected or TB-uninfected difficult. Existing tools for the diagnosis of TB infection are unsatisfactory in determining infection among children in this setting.
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Within-subject interlaboratory variability of QuantiFERON-TB gold in-tube tests. PLoS One 2012; 7:e43790. [PMID: 22970142 PMCID: PMC3435391 DOI: 10.1371/journal.pone.0043790] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 07/23/2012] [Indexed: 11/30/2022] Open
Abstract
Background The QuantiFERON®-TB Gold In-Tube test (QFT-GIT) is a viable alternative to the tuberculin skin test (TST) for detecting Mycobacterium tuberculosis infection. However, within-subject variability may limit test utility. To assess variability, we compared results from the same subjects when QFT-GIT enzyme-linked immunosorbent assays (ELISAs) were performed in different laboratories. Methods Subjects were recruited at two sites and blood was tested in three labs. Two labs used the same type of automated ELISA workstation, 8-point calibration curves, and electronic data transfer. The third lab used a different automated ELISA workstation, 4-point calibration curves, and manual data entry. Variability was assessed by interpretation agreement and comparison of interferon-γ (IFN-γ) measurements. Data for subjects with discordant interpretations or discrepancies in TB Response >0.05 IU/mL were verified or corrected, and variability was reassessed using a reconciled dataset. Results Ninety-seven subjects had results from three labs. Eleven (11.3%) had discordant interpretations and 72 (74.2%) had discrepancies >0.05 IU/mL using unreconciled results. After correction of manual data entry errors for 9 subjects, and exclusion of 6 subjects due to methodological errors, 7 (7.7%) subjects were discordant. Of these, 6 (85.7%) had all TB Responses within 0.25 IU/mL of the manufacturer's recommended cutoff. Non-uniform error of measurement was observed, with greater variation in higher IFN-γ measurements. Within-subject standard deviation for TB Response was as high as 0.16 IU/mL, and limits of agreement ranged from −0.46 to 0.43 IU/mL for subjects with mean TB Response within 0.25 IU/mL of the cutoff. Conclusion Greater interlaboratory variability was associated with manual data entry and higher IFN-γ measurements. Manual data entry should be avoided. Because variability in measuring TB Response may affect interpretation, especially near the cutoff, consideration should be given to developing a range of values near the cutoff to be interpreted as “borderline,” rather than negative or positive.
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Validation of increased blood storage times with the T-SPOT.TB assay with T-Cell Xtend reagent in individuals with different tuberculosis risk factors. J Clin Microbiol 2012; 50:2469-71. [PMID: 22518862 DOI: 10.1128/jcm.00674-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared the performance of the T-SPOT.TB assay with blood used within 0 to 3.5 h after collection (control) to its performance with blood stored for 0 to 3.5, 5 to 8, 18 to 21, or 31 to 33 h with the addition of T-Cell Xtend (experimental), using samples from 154 participants. The 95.4% concordance between paired specimens indicated that blood can be stored for up to 33 h prior to T-SPOT.TB testing.
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Santin M, Muñoz L, Rigau D. Interferon-γ release assays for the diagnosis of tuberculosis and tuberculosis infection in HIV-infected adults: a systematic review and meta-analysis. PLoS One 2012; 7:e32482. [PMID: 22403663 PMCID: PMC3293815 DOI: 10.1371/journal.pone.0032482] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 01/30/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Despite the widespread use of interferon-γ release assays (IGRAs), their role in diagnosing tuberculosis and targeting preventive therapy in HIV-infected patients remains unclear. We conducted a comprehensive systematic review to contribute to the evidence-based practice in HIV-infected people. METHODOLOGY/PRINCIPAL FINDINGS We searched MEDLINE, Cochrane, and Biomedicine databases to identify articles published between January 2005 and July 2011 that assessed QuantiFERON®-TB Gold In-Tube (QFT-GIT) and T-SPOT®.TB (T-SPOT.TB) in HIV-infected adults. We assessed their accuracy for the diagnosis of tuberculosis and incident active tuberculosis, and the proportion of indeterminate results. The search identified 38 evaluable studies covering a total of 6514 HIV-infected participants. The pooled sensitivity and specificity for tuberculosis were 61% and 72% for QFT-GIT, and 65% and 70% for T-SPOT.TB. The cumulative incidence of subsequent active tuberculosis was 8.3% for QFT-GIT and 10% for T-SPOT.TB in patients tested positive (one study each), and 0% for QFT-GIT (two studies) and T-SPOT.TB (one study) respectively in those tested negative. Pooled indeterminate rates were 8.2% for QFT-GIT and 5.9% for T-SPOT.TB. Rates were higher in high burden settings (12.0% for QFT-GIT and 7.7% for T-SPOT.TB) than in low-intermediate burden settings (3.9% for QFT-GIT and 4.3% for T-SPOT.TB). They were also higher in patients with CD4(+) T-cell count <200 (11.6% for QFT-GIT and 11.4% for T-SPOT.TB) than in those with CD4(+) T-cell count ≥ 200 (3.1% for QFT-GIT and 7.9% for T-SPOT.TB). CONCLUSIONS/SIGNIFICANCE IGRAs have suboptimal accuracy for confirming or ruling out active tuberculosis disease in HIV-infected adults. While their predictive value for incident active tuberculosis is modest, a negative QFT-GIT implies a very low short- to medium-term risk. Identifying the factors associated with indeterminate results will help to optimize the use of IGRAs in clinical practice, particularly in resource-limited countries with a high prevalence of HIV-coinfection.
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Affiliation(s)
- Miguel Santin
- Department of Infectious Diseases, Bellvitge University Hospital-IDIBELL, L'Hospitalet, Barcelona, Spain.
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Pai M, Elwood K. Interferon-gamma release assays for screening of health care workers in low tuberculosis incidence settings: dynamic patterns and interpretational challenges. Can Respir J 2012; 19:81-3. [PMID: 22536575 PMCID: PMC3373289 DOI: 10.1155/2012/420392] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Madhukar Pai
- Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute
- Department of Epidemiology & Biostatistics, McGill University, Montreal, Quebec
| | - Kevin Elwood
- BC Centre for Disease Control & University of British Columbia, Vancouver, British Columbia
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