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Monteiro AA, Rubenich DS, Zandoná MR, Pasqualotto AC. Impact of pre-analytical variables in the determination of serum galactomannan. Med Mycol 2017; 55:635-641. [PMID: 27838643 DOI: 10.1093/mmy/myw123] [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: 06/10/2016] [Accepted: 10/20/2016] [Indexed: 11/14/2022] Open
Abstract
Invasive aspergillosis (IA) is associated with a high morbidity and mortality. Since Aspergillus species are usually not cultured in these patients, presumptive diagnosis of IA is more commonly based on galactomannan (GM) detection. Several factors are known to cause false-positive results in the GM test, but little is known on the influence of pre-analytical variables interfering on the test. Here we studied the influence of temperature and sample storage duration in GM results, using samples known to be negative and positive (spiked) for GM. We also evaluated the effect of hemolysis and hyperbilirubinemia on GM optical indexes. We found no influence of storage time (up to 96 h) and temperatures (refrigerated vs. RT) on GM results. However, bilirubin (P = .022) and haemoglobin (P = .003) content influenced GM readings in samples known for being GM positive and negative at baseline, respectively. We conclude that the Platelia GM test does not suffer major influence of pre-analytical variables such as storage conditions, and low levels of hemolysis and hyperbilirubinemia. Nonetheless, massive haemolysis seems to interfere with GM readings in GM-negative samples, and high levels of bilirubin can affect GM readings in samples that are positive for GM at baseline. These findings may facilitate logistics and the implementation of standard operational procedures in clinical laboratories.
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Affiliation(s)
- Alexandre A Monteiro
- Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.,Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, Brazil
| | - Dominique S Rubenich
- Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Marilia R Zandoná
- Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Alessandro C Pasqualotto
- Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.,Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, Brazil
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2
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Leeflang MMG, Debets‐Ossenkopp YJ, Wang J, Visser CE, Scholten RJPM, Hooft L, Bijlmer HA, Reitsma JB, Zhang M, Bossuyt PMM, Vandenbroucke‐Grauls CM. Galactomannan detection for invasive aspergillosis in immunocompromised patients. Cochrane Database Syst Rev 2015; 2015:CD007394. [PMID: 26716951 PMCID: PMC6483812 DOI: 10.1002/14651858.cd007394.pub2] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Invasive aspergillosis is the most common life-threatening opportunistic invasive mycosis in immunocompromised patients. A test for invasive aspergillosis should neither be too invasive nor too great a burden for the already weakened patient. The serum galactomannan enzyme-linked immunosorbent assay (ELISA) seems to have the potential to meet both requirements. OBJECTIVES To obtain summary estimates of the diagnostic accuracy of galactomannan detection in serum for the diagnosis of invasive aspergillosis. SEARCH METHODS We searched MEDLINE, EMBASE and Web of Science with both MeSH terms and text words for both aspergillosis and the sandwich ELISA. We checked the reference lists of included studies and review articles for additional studies. We conducted the searches in February 2014. SELECTION CRITERIA We included cross-sectional studies, case-control designs and consecutive series of patients assessing the diagnostic accuracy of galactomannan detection for the diagnosis of invasive aspergillosis in patients with neutropenia or patients whose neutrophils are functionally compromised. The reference standard was composed of the criteria given by the European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG). DATA COLLECTION AND ANALYSIS Two review authors independently assessed quality and extracted data. We carried out meta-analysis using the bivariate method. We investigated sources of heterogeneity by adding potential sources of heterogeneity to the model as covariates. MAIN RESULTS We included 54 studies in the review (50 in the meta-analyses), containing 5660 patients, of whom 586 had proven or probable invasive aspergillosis. When using an optical density index (ODI) of 0.5 as a cut-off value, the sensitivity of the test was 82% (73% to 90%) and the specificity was 81% (72% to 90%). At a cut-off value of 1.0 ODI, the sensitivity was 72% (65% to 80%) and the specificity was 88% (84% to 92%). At a cut-off value of 1.5 ODI, the sensitivity was 61% (47% to 75%) and the specificity was 93% (89% to 97%). None of the potential sources of heterogeneity had a statistically significant effect on either sensitivity or specificity. AUTHORS' CONCLUSIONS If we used the test at a cut-off value of 0.5 ODI in a population of 100 patients with a disease prevalence of 9% (overall median prevalence), two patients who have invasive aspergillosis would be missed (sensitivity 82%, 18% false negatives), and 17 patients would be treated unnecessarily or referred unnecessarily for further testing (specificity 81%, 19% false negatives). If we used the test at a cut-off value of 1.5 in the same population, that would mean that four invasive aspergillosis patients would be missed (sensitivity 61%, 39% false negatives), and six patients would be treated or referred for further testing unnecessarily (specificity 93%, 7% false negatives). These numbers should, however, be interpreted with caution because the results were very heterogeneous.
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Affiliation(s)
- Mariska MG Leeflang
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsP.O. Box 22700AmsterdamNetherlands1100 DE
| | - Yvette J Debets‐Ossenkopp
- VU University Medical CenterDepartment of Medical Microbiology and Infection ControlPO Box 7057AmsterdamNetherlands1007 MB
| | - Junfeng Wang
- Academic Medical CenterDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsMeibergdreef 9AmsterdamNetherlands1105 AZ
| | - Caroline E Visser
- Academic Medical CentreDepartment of Medical MicrobiologyAmsterdamNetherlands
| | - Rob JPM Scholten
- Julius Center for Health Sciences and Primary Care / University Medical Center UtrechtCochrane NetherlandsRoom Str. 6.126P.O. Box 85500UtrechtNetherlands3508 GA
| | - Lotty Hooft
- Julius Center for Health Sciences and Primary Care / University Medical Center UtrechtCochrane NetherlandsRoom Str. 6.126P.O. Box 85500UtrechtNetherlands3508 GA
| | - Henk A Bijlmer
- Bronovo HospitalDepartment of Clinical Microbiology and Infection ControlThe HagueNetherlands
| | - Johannes B Reitsma
- University Medical Center UtrechtJulius Center for Health Sciences and Primary CarePO Box 85500UtrechtNetherlands3508 GA Utrecht
| | - Mingming Zhang
- West China Hospital, Sichuan UniversityChinese Cochrane Centre, Chinese Evidence‐Based Medicine CentreNo. 37, Guo Xue XiangChengduSichuanChina610041
| | - Patrick MM Bossuyt
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsP.O. Box 22700AmsterdamNetherlands1100 DE
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Ambasta A, Carson J, Church DL. The use of biomarkers and molecular methods for the earlier diagnosis of invasive aspergillosis in immunocompromised patients. Med Mycol 2015; 53:531-57. [DOI: 10.1093/mmy/myv026] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 04/08/2015] [Indexed: 12/15/2022] Open
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4
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Insufficient demonstration of long-term stability of Aspergillus galactomannan. J Clin Microbiol 2015; 52:4118. [PMID: 25324240 DOI: 10.1128/jcm.02342-14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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5
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Johnson G, Ferrini A, Dolan SK, Nolan T, Agrawal S, Doyle S, Bustin SA. Biomarkers for invasive aspergillosis: the challenges continue. Biomark Med 2014; 8:429-51. [PMID: 24712434 DOI: 10.2217/bmm.13.129] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The incidence of invasive aspergillosis (IA), an opportunistic infection in immunocompromised individuals, is rising, but its early diagnosis remains challenging and treatment options are limited. Hence there is an urgent need to improve existing diagnostic procedures as well as develop novel approaches. The clinical usefulness of galactomannan and β-d-glucan, widely used assays detecting cell-wall antigens of Aspergillus, is unclear and depends on clinicians' awareness of their practical limitations. This leaves room for new methods that utilise genomic, proteomic and metabolomics approaches as well as novel detection procedures, for example point-of-care lateral-flow devices. Each of these strategies has its own limitations and it is likely that a combination of methods will be required to achieve optimal performance for the diagnosis of IA and subsequent appropriate patient management.
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Affiliation(s)
- Gemma Johnson
- Blizard Institute, Queen Mary University of London, London, UK
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6
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Instability of Aspergillus galactomannan in stored clinical samples. J Clin Microbiol 2014; 52:4435-6. [PMID: 25253794 DOI: 10.1128/jcm.01912-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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7
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Long-term stability at -20 °C of Aspergillus galactomannan in serum and bronchoalveolar lavage specimens. J Clin Microbiol 2014; 52:2108-11. [PMID: 24719449 DOI: 10.1128/jcm.03500-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Research to develop and validate novel methods for diagnosis of aspergillosis based on detection of galactomannan requires the use of clinical specimens that have been stored frozen. Data indicating that galactomannan remains stable when frozen are scant. The objective of this study was to determine the stability of galactomannan in clinical specimens stored at -20 °C that were positive in the Platelia Aspergillus enzyme immunoassay when initially tested. Prospective real-time testing of serum and bronchoalveolar lavage (BAL) fluid pools from positive and negative patient specimens showed no decline in galactomannan index (GMI) over 11 months at -20 °C and no development of positive reactions in the negative-control pool. Retrospective testing of positive specimens that had been stored at -20 °C for 5 years showed that 28 of 30 serum (n = 15) or BAL (n = 15) specimens remained positive. These findings support the use of frozen serum or BAL specimens stored for at least 5 years in evaluation of diagnostic tests based on detection of galactomannan.
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Johnson GL, Sarker SJ, Hill K, Tsitsikas DA, Morin A, Bustin SA, Agrawal SG. Significant decline in Galactomannan Signal during storage of clinical serum samples. Int J Mol Sci 2013; 14:12970-7. [PMID: 23797658 PMCID: PMC3742168 DOI: 10.3390/ijms140712970] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 06/07/2013] [Accepted: 06/13/2013] [Indexed: 11/21/2022] Open
Abstract
Galactomannan (GM) is widely used for detection of invasive aspergillosis in high-risk haemato-oncology patients. Recent publications have reported a lack of repeatability of GM detection. The objective of this retrospective study was to assess the repeatability of GM levels during storage of clinical samples. In a GM screening strategy, positive sera were repeat tested as per manufacturer’s recommendations. Short-term (ST) storage of samples was at +4 °C while long-term (LT) storage was at −80 °C. Bronchoalveolar (BAL) fluid was also repeating tested after ST storage and LT storage. Wilcoxon Signed Ranks Test was employed to assess the repeatability of GM levels. In a subset of 14 GM positive sera, repeat testing was performed on both the original serum and ethylenediaminetetraacetic acid (EDTA) pre-treated sample. There was a significant reduction in GM signals on repeat testing following ST storage (median GM index: 0.65 vs. 0.19; p < 0.001) and LT storage (median GM index: 0.56 vs. 0.10; p < 0.001) of serum samples. Of samples that were initially GM positive, an average GM index reduction of 50% was seen, with approximately two-thirds becoming GM negative on repeat testing of the same sample. In contrast, GM signal loss was not seen on repeat testing of BAL fluid following ST or LT storage. When GM positive serum samples were repeat tested using EDTA pre-treated serum from the first step of the testing protocol, all samples remained GM positive. In contrast, when the same samples were repeat tested from the original collected serum, 9 samples (64%) became GM negative. The significant reduction in GM signals during ST and LT storage of serum samples has implications for clinical management. Although the reasons for GM decline are unknown, they occur prior to the EDTA pre-treatment stage, indicating that the time from phlebotomy to testing should be minimized. BAL fluid GM index values remain stable.
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Affiliation(s)
- Gemma L. Johnson
- Blizard Institute of Cell and Molecular Science, Queen Mary University of London, London E1 2AT, UK; E-Mail:
| | - Shah-Jalal Sarker
- Centre for Experimental Cancer Medicine, Barts Cancer Institute, Queen Mary University of London, London EC1M 6BQ, UK; E-Mail:
| | - Kate Hill
- Division of Infection, Barts Health NHS Trust, London E1 2ES, UK; E-Mail:
| | - Dimitris A. Tsitsikas
- Department of Haemato-Oncology, St Bartholomew’s Hospital, London EC1A 7BE, UK; E-Mails: (D.A.T.); (A.M.)
| | - Amelie Morin
- Department of Haemato-Oncology, St Bartholomew’s Hospital, London EC1A 7BE, UK; E-Mails: (D.A.T.); (A.M.)
| | - Stephen A. Bustin
- Postgraduate Medical Institute, Faculty of Health, Social Care & Education, Anglia Ruskin University, Chelmsford CM1 1SQ, UK; E-Mail:
| | - Samir G. Agrawal
- Blizard Institute of Cell and Molecular Science, Queen Mary University of London, London E1 2AT, UK; E-Mail:
- Department of Haemato-Oncology, St Bartholomew’s Hospital, London EC1A 7BE, UK; E-Mails: (D.A.T.); (A.M.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44-203-465-5993; Fax: +44-203-465-5992
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Krishnan S, Manavathu EK, Chandrasekar PH. Aspergillus flavus: an emerging non-fumigatus Aspergillus species of significance. Mycoses 2009; 52:206-22. [PMID: 19207851 DOI: 10.1111/j.1439-0507.2008.01642.x] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Invasive aspergillosis is rare in immunocompetent people but contributes to significant morbidity and mortality in immunosuppressed patients. The majority (approximately 80%) of invasive Aspergillus infections is caused by Aspergillus fumigatus. The second most frequent (approximately 15-20%) pathogenic species is Aspergillus flavus and to a lesser extent, Aspergillus niger and Aspergillus terreus. Aspergillus flavus has emerged as a predominant pathogen in patients with fungal sinusitis and fungal keratitis in several institutions worldwide. To date, there has not been any publication exclusively reviewing the topic of A. flavus in the literature. This article reviews the microbiology, toxigenicity and epidemiology of A. flavus as well as describes the clinical characteristics, diagnosis and management of infections caused by this organism.
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Affiliation(s)
- Suganthini Krishnan
- Division of Infectious Diseases, Wayne State University, John D. Dingell VA Medical Center, Detroit, MI 48201, USA.
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10
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Hlava N, Niemann CU, Gropper MA, Melcher ML. Postoperative infectious complications of abdominal solid organ transplantation. J Intensive Care Med 2008; 24:3-17. [PMID: 19017663 DOI: 10.1177/0885066608327127] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
There is a rapidly growing population of immunocompromised organ transplant recipients. These patients are at risk of a large variety of infections that have significant consequences on mortality, graft dysfunction, and graft loss. The diagnosis and treatment of these infections are facilitated by an understanding of the preoperative, perioperative, and postoperative risk factors; the typical pathogens; and their characteristic time of presentation. On the basis of these factors, we put forth an algorithm for diagnosing and treating suspected infections in solid organ transplant recipients.
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Affiliation(s)
- Nicole Hlava
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA
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Leeflang MM, Debets-Ossenkopp YJ, Visser CE, Scholten RJPM, Hooft L, Bijlmer HA, Reitsma JB, Bossuyt PM, Vandenbroucke-Grauls CM. Galactomannan detection for invasive aspergillosis in immunocompromized patients. Cochrane Database Syst Rev 2008:CD007394. [PMID: 18843747 DOI: 10.1002/14651858.cd007394] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Invasive aspergillosis (IA) is the most common life-threatening opportunistic invasive mycosis in immunocompromized patients. A test for IA needs to be not too invasive and not too big a burden for the already weakened patient. The serum galactomannan ELISA seems to have potential for both requirements. OBJECTIVES To obtain summary estimates of the diagnostic accuracy of galactomannan detection in serum for the diagnosis of IA. SEARCH STRATEGY We searched MEDLINE, EMBASE and Web of Science with both Medical Headings and text words for both aspergillosis and the sandwich ELISA. We checked reference lists of included studies and review articles for additional studies. SELECTION CRITERIA Cross-sectional studies, case-control designs and consecutive series of patients assessing the diagnostic accuracy of galactomannan detection for the diagnosis of IA in patients with neutropenia or patients whose neutrophils are functionally compromised were included. The reference standard was composed of the criteria given by the European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG). DATA COLLECTION AND ANALYSIS Two review authors independently assessed quality and extracted data MAIN RESULTS Thirty studies were included in the meta-analyses, with a median prevalence of IA (proven or probable) of 7.7%. Seven of these (901 patients) reported results for an Optical Density Index (ODI) of 0.5 as cut-off value. The overall sensitivity in these studies was 78% (61% to 89%) and overall specificity was 81% (72% to 88%). Twelve studies (1744 patients) reported the results for cut-off value of 1.0 ODI, overall sensitivity was 75% (59% to 86%) and mean specificity 91% (84% to 95%). Seventeen studies (2600 patients) reported the results for cut-off value 1.5 ODI, sensitivity was 64% (50% to 77%) and mean specificity 95% (91% to 97%). AUTHORS' CONCLUSIONS At a cut-off value 0.5 ODI in a population of 100 patients with a disease prevalence of 8% (overall median prevalence), 2 patients who have IA, will be missed (sensitivity 78%, 22% false negatives), and 17 patients will be treated or further referred unnecessarily (specificity of 81%, 19% false negatives). If we use the test at cut-off value 1.5 in the same population, that will mean that 3 IA patients will be missed (sensitivity 64%, 36% false negatives) and 5 patients will be treated or referred unnecessarily (specificity of 95%, 5% false negatives). These numbers should however be interpreted with caution, because the results were very heterogeneous.
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Affiliation(s)
- Mariska M Leeflang
- Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, J1B-210, P.O. Box 22700 , AMSTERDAM, Netherlands, 1100 DE.
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12
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Miceli M, Grazziutti M, Woods G, Zhao W, Kocoglu M, Barlogie B, Anaissie E. Strong Correlation between Serum Aspergillus Galactomannan Index and Outcome of Aspergillosis in Patients with Hematological Cancer: Clinical and Research Implications. Clin Infect Dis 2008; 46:1412-22. [DOI: 10.1086/528714] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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13
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Steinbach WJ, Addison RM, McLaughlin L, Gerrald Q, Martin PL, Driscoll T, Bentsen C, Perfect JR, Alexander BD. Prospective Aspergillus galactomannan antigen testing in pediatric hematopoietic stem cell transplant recipients. Pediatr Infect Dis J 2007; 26:558-64. [PMID: 17596794 DOI: 10.1097/inf.0b013e3180616cbb] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The galactomannan (GM) assay is an approved noninvasive test for detection of invasive aspergillosis (IA) that has been validated in adult patients with hematologic malignancies who are undergoing bone marrow transplantation. There have been few studies with this assay in pediatric patients, but early reports suggest that there may be differences in the performance such that false-positive GM tests in pediatric patients are more common than in adult patients. METHODS We performed a prospective study in pediatric hematopoietic stem cell transplant recipients with twice-weekly sampling for GM detection during the highest risk periods of neutropenia and graft-versus-host disease. We analyzed 826 serum samples from 64 patients, including 15 serum samples from one patient diagnosed with probable IA according to defined criteria. RESULTS Twenty of 811 samples tested positive on repeat testing (specificity, 97.5%; 95% CI: 96.2-98.4%) including samples from 8 of 63 patients without clinical evidence of IA according to study criteria (specificity, 87.3%; 95% CI: 76.9-93.4%). Eleven patients received piperacillin/tazobactam therapy, and 4 of the 11 patients had a positive assay result coinciding with the dates of piperacillin/tazobactam administration. When samples from these patients were excluded, specificity increased to 98.4% (95% CI: 97.2-99.1%) by sample and to 91.5% (95% CI: 81.6-96.3%) by patient. CONCLUSIONS The GM assay holds promise for early, noninvasive diagnosis of IA in high-risk children and false-positive results were not common or unexplainable. This study supports further validation of this assay in a large-scale, pediatric-dedicated format.
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Affiliation(s)
- William J Steinbach
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
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Maertens J, Theunissen K, Lodewyck T, Lagrou K, Van Eldere J. Advances in the serological diagnosis of invasive Aspergillus infections in patients with haematological disorders. Mycoses 2007; 50 Suppl 1:2-17. [PMID: 17394605 DOI: 10.1111/j.1439-0507.2007.01375.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A reliable diagnosis of invasive aspergillosis in patients with haematological malignancies is seldom achieved antemortem. Conventional laboratory diagnostic methods are insensitive and time-consuming, resulting in late diagnosis and treatment and contributing to unacceptably high mortality. As a result, routine antifungal prophylaxis and early empirical treatment have been recommended. However, overtreatment associated with these strategies results in increased toxicity and cost. The use of sensitive and rapid non-culture-based diagnostic assays, such as detection of Aspergillus antigens (galactomannan, beta-D-glucan) or detection of genomic DNA sequences may allow a shift in emphasis from empirical to pre-emptive therapy, especially when substantiated by suggestive radiological findings. These new tools may be used to confirm a presumed diagnosis of invasive aspergillosis, or, when used to screen high-risk patients, may identify an infection at the early stage of disease. The excellent negative predictive value of these assays should convince clinicians to withhold antifungal therapy in persistently febrile neutropenic patients with no other signs of fungal infection. On the other hand, consecutive positive results in a high-risk population should at least trigger a complete diagnostic work-up. This review will focus on the diagnostic utility as well as on the pitfalls of serial screening for the presence of circulating fungal antigens in haematology patients.
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Affiliation(s)
- Johan Maertens
- Department of Haematology, Universitaire Ziekenhuizen Leuven, Catholic University, Leuven, Belgium.
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15
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Aquino VR, Goldani LZ, Pasqualotto AC. Update on the contribution of galactomannan for the diagnosis of invasive aspergillosis. Mycopathologia 2007; 163:191-202. [PMID: 17410480 DOI: 10.1007/s11046-007-9010-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 03/11/2007] [Indexed: 10/23/2022]
Abstract
The diagnosis of invasive fungal infections (IFI) remains a challenge, particularly for diseases caused by filamentous fungi such as Aspergillus species. Unfortunately, many patients affected by these conditions are not identified before autopsy. Therefore, there is a need for new diagnostic methods for IFI. Galactomannan is a soluble antigen released during hyphal growth in tissues. A commercially available sandwich ELISA assay that detects galactomannan has been used in Europe for many years and is now approved for use in the USA. The test has an excellent negative predictive value in the detection of invasive aspergillosis (IA) in high-risk patients. In addition, it is more sensitive than culture and allows IA to be diagnosed before clinical manifestations occur. However, false-negative and false-positive results in certain populations are the main limitations to its use. The purpose of this review is to summarize the current knowledge about galactomannan testing in patients at risk for IA.
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Affiliation(s)
- Valério R Aquino
- Mycology Laboratory, Service of Clinical Pathology, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil
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