Diagnostic accuracy of same-day microscopy versus standard microscopy for pulmonary tuberculosis: a systematic review and meta-analysis

Bringing patient-centered tuberculosis diagnosis into the light of day

In 2015, the WHO End TB Strategy laid out ambitious goals to dramatically reduce tuberculosis (TB) deaths, incidence, and catastrophic costs through research, bold new strategies, and patient-centered care. In this commentary, recent evidence on sputum collection strategies for smear microscopy is reviewed, and the argument is made that redesigning smear microscopy as a patient-centered service offers the only realistic and widely available strategy to advance TB diagnostic care towards the initial End TB Strategy goals laid out for 2025. Finally, the successful adoption of same-day sputum smear microscopy as a model for patient-centered TB care is suggested to be synergistic with and to form part of the scale-up of new TB diagnostic tools.Please see related article: https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-017-0947-9.

Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis

BACKGROUND

The use of early morning sputum samples (EMS) to diagnose tuberculosis (TB) can result in treatment delay given the need for the patient to return to the clinic with the EMS, increasing the chance of patients being lost during their diagnostic workup. However, there is little evidence to support the superiority of EMS over spot sputum samples. In this new analysis of the REMoxTB study, we compare the diagnostic accuracy of EMS with spot samples for identifying Mycobacterium tuberculosis pre- and post-treatment.

METHODS

Patients who were smear positive at screening were enrolled into the study. Paired sputum samples (one EMS and one spot) were collected at each trial visit pre- and post-treatment. Microscopy and culture on solid LJ and liquid MGIT media were performed on all samples; those missing corresponding paired results were excluded from the analyses.

RESULTS

Data from 1115 pre- and 2995 post-treatment paired samples from 1931 patients enrolled in the REMoxTB study were analysed. Patients were recruited from South Africa (47%), East Africa (21%), India (20%), Asia (11%), and North America (1%); 70% were male, median age 31 years (IQR 24-41), 139 (7%) co-infected with HIV with a median CD4 cell count of 399 cells/μL (IQR 318-535). Pre-treatment spot samples had a higher yield of positive Ziehl-Neelsen smears (98% vs. 97%, P = 0.02) and LJ cultures (87% vs. 82%, P = 0.006) than EMS, but there was no difference for positivity by MGIT (93% vs. 95%, P = 0.18). Contaminated and false-positive MGIT were found more often with EMS rather than spot samples. Surprisingly, pre-treatment EMS had a higher smear grading and shorter time-to-positivity, by 1 day, than spot samples in MGIT culture (4.5 vs. 5.5 days, P < 0.001). There were no differences in time to positivity in pre-treatment LJ culture, or in post-treatment MGIT or LJ cultures. Comparing EMS and spot samples in those with unfavourable outcomes, there were no differences in smear or culture results, and positive results were not detected earlier in Kaplan-Meier analyses in either EMS or spot samples.

CONCLUSIONS

Our data do not support the hypothesis that EMS samples are superior to spot sputum samples in a clinical trial of patients with smear positive pulmonary TB. Observed small differences in mycobacterial burden are of uncertain significance and EMS samples do not detect post-treatment positives any sooner than spot samples.

A proposed novel framework for monitoring and evaluation of the cascade of HIV-associated TB care at the health facility level

INTRODUCTION

The rapid and accurate diagnosis of HIV-associated tuberculosis (TB), timely initiation of curative or preventative treatment and assurance of favourable treatment outcomes is a complex process. The current system of monitoring and reporting TB diagnosis and treatment does not include several key aspects of the care cascade, and may obscure systematic bottlenecks, inefficiencies or sources of sub-optimal care.

METHODS

We critically reviewed the current World Health Organizations recommended system of monitoring and reporting, and identified the following key deficiencies that could limit the ability of healthcare workers to identify structural problems in the provision of TB/HIV care.

RESULTS

We identified the following key deficiencies in the current monitoring and evaluation system: (1) an emphasis on national-level reporting and programmatic analysis results in a loss of granularity; (2) the absence of a general framework to anchor indicators in relation to one another as well as the overall goals for TB/HIV collaborative activities; (3) de-linking of TB treatment indicators from those for screening and diagnosis; (4) few indicators are tied to suggested times for completion of an activity. We defined three distinct stages comprising the cascade of HIV-associated TB diagnosis and treatment: (1) Screening & Diagnosis, (2) Treatment and (3) Preventive Therapy. We detailed major steps within each stage, described potential sources of variability, and proposed data elements, process indicators, main outcomes, and retention calculations for each stage.

CONCLUSION

This proposed framework of monitoring is novel in its focus on a cohort experience through the entire scope of the care cascade from screening and TB diagnosis through curative or preventive treatment. This approach can be applied to all settings at clinic, district or national level, and used to identify crucial areas for improvement in order to maximize health outcomes for all those affected by the dual epidemics of TB and HIV.

Feasibility of two active case finding approaches for detection of tuberculosis in Bandung City, Indonesia

Setting: A community health clinic catchment area in the eastern part of Bandung City, Indonesia. Objective: To evaluate the feasibility of two different screening interventions using community health workers (CHWs) in detecting tuberculosis (TB) cases. Design: This was a feasibility study of 1) house-to-house TB symptom screening of five randomly selected 'neighbourhoods' in the catchment area, and 2) selected screening of household contacts of TB index patients and their neighbouring households. Acceptability was assessed through focus group discussions with key stakeholders. Results: Of 5100 individuals screened in randomly selected neighbourhoods, 48 (0.9%) reported symptoms, of whom 38 provided sputum samples; no positive TB was found. No TB cases were found among the 88 household contacts or the 423 neighbourhood contacts. With training, regular support and supervision from research staff and local community health centre staff, CHWs were able to undertake screening effectively, and almost all householders were willing to participate. Conclusion: The use of CHWs for TB screening could be integrated into routine practice relatively easily in Indonesia. The effectiveness of this would need further exploration, particularly with the use of improved diagnostics such as chest X-ray and sputum culture.

The value of one versus three sputum smear examinations for diagnosis of pulmonary tuberculosis in Asella hospital, South-East Ethiopia

OBJECTIVE

The aim of the study is to compare the value of a single with three sputum smear examinations in the detection of smear-positive pulmonary tuberculosis.

RESULTS

There were a total of 7012 patients studied out of which 3599 (51.3%) were males and the rest females. In 637 (9.1%) of the patients, two or more smears were positive for AFB. 616 (96.7%) of the sputum smear positive patients had positive smears on the first spot sputum exams as compared to 635 (99.7%) who were positive on the morning sputum, (P = 0.000064). 598/637 (93.9%) of sputum smear positive patients had positive smears in all three smears regardless of the smear grading. A single morning smear examination is as sensitive as doing three sputum smear examinations in the diagnosis of sputum smear positive TB. The incidence of sputum smear positivity differed significantly across age groups, but did not differ between genders.

Tuberculosis patients in an Indian mega-city: Where do they live and where are they diagnosed?

Objective

Tuberculosis (TB) is a major source of mortality in urban India, with many structural challenges to optimal care delivery. In the government TB program in Chennai, India’s fourth most populous city, there is a 49% gap between the official number of smear-positive TB patients diagnosed and the official number registered in TB treatment within the city in 2014. We hypothesize that this “urban registration gap” is partly due to rural patients temporarily visiting the city for diagnostic evaluation.

Methods

We collected data for one month (May 2015) from 22 government designated microscopy centers (DMCs) in Chennai where 90% of smear-positive TB patients are diagnosed and coded patient addresses by location. We also analyzed the distribution of chest symptomatics (i.e., patients screened for TB because of pulmonary symptoms) and diagnosed smear-positive TB patients for all of Chennai’s 54 DMCs in 2014.

Results

At 22 DMCs in May 2015, 565 of 3,543 (15.9%) chest symptomatics and 71 of 412 (17.2%) diagnosed smear-positive patients had an address outside of Chennai. At the city’s four high patient volume DMCs, 54 of 270 (20.0%) smear-positive patients lived out-of-city. At one of these high-volume DMCs, 31 of 59 (52.5%) smear-positive patients lived out-of-city. Out of 6,135 smear-positive patients diagnosed in Chennai in 2014, 3,498 (57%) were diagnosed at the four high-volume DMCs. The 32 DMCs with the lowest patient volume diagnosed 10% of all smear-positive patients.

Conclusions

TB case detection in Chennai is centralized, with four high-volume DMCs making most diagnoses. One-sixth of patients are from outside the city, most of whom get evaluated at these high-volume DMCs. This calls for better coordination between high-volume city DMCs and rural TB units where many patients may take TB treatment. Patient mobility only partly explains Chennai’s urban registration gap, suggesting that pretreatment loss to follow-up of patients who live within the city may also be a major problem.

Comparison of sputum collection methods for tuberculosis diagnosis: a systematic review and pairwise and network meta-analysis

BACKGROUND

The performance of laboratory tests to diagnose pulmonary tuberculosis is dependent on the quality of the sputum sample tested. The relative merits of sputum collection methods to improve tuberculosis diagnosis are poorly characterised. We therefore aimed to investigate the effects of sputum collection methods on tuberculosis diagnosis.

METHODS

We did a systematic review and meta-analysis to investigate whether non-invasive sputum collection methods in people aged at least 12 years improve the diagnostic performance of laboratory testing for pulmonary tuberculosis. We searched PubMed, Google Scholar, ProQuest, Web of Science, CINAHL, and Embase up to April 14, 2017, to identify relevant experimental, case-control, or cohort studies. We analysed data by pairwise meta-analyses with a random-effects model and by network meta-analysis. All diagnostic performance data were calculated at the sputum-sample level, except where authors only reported data at the individual patient-level. Heterogeneity was assessed, with potential causes identified by logistic meta-regression.

FINDINGS

We identified 23 eligible studies published between 1959 and 2017, involving 8967 participants who provided 19 252 sputum samples. Brief, on-demand spot sputum collection was the main reference standard. Pooled sputum collection increased tuberculosis diagnosis by microscopy (odds ratio [OR] 1·6, 95% CI 1·3-1·9, p<0·0001) or culture (1·7, 1·2-2·4, p=0·01). Providing instructions to the patient before sputum collection, during observed collection, or together with physiotherapy assistance increased diagnostic performance by microscopy (OR 1·6, 95% CI 1·3-2·0, p<0·0001). Collecting early morning sputum did not significantly increase diagnostic performance of microscopy (OR 1·5, 95% CI 0·9-2·6, p=0·2) or culture (1·4, 0·9-2·4, p=0·2). Network meta-analysis confirmed these findings, and revealed that both pooled and instructed spot sputum collections were similarly effective techniques for increasing the diagnostic performance of microscopy.

INTERPRETATION

Tuberculosis diagnoses were substantially increased by either pooled collection or by providing instruction on how to produce a sputum sample taken at any time of the day. Both interventions had a similar effect to that reported for the introduction of new, expensive laboratory tests, and therefore warrant further exploration in the drive to end the global tuberculosis epidemic.

FUNDING

Wellcome Trust, Joint Global Health Trials consortium, Innovation For Health and Development, and Bill & Melinda Gates Foundation.

Implementation and Operational Research: Population-Based Active Tuberculosis Case Finding During Large-Scale Mobile HIV Testing Campaigns in Rural Uganda

BACKGROUND

Active tuberculosis (TB) screening outside clinics and in communities may reduce undiagnosed TB.

METHODS

To determine the yield of TB screening during community-based HIV testing campaigns (CHC) in 7 rural Ugandan communities within an ongoing cluster-randomized trial of universal HIV testing and treatment (SEARCH, NCT:01864603), we offered sputum microscopy to participants with prolonged cough (>2 weeks). We determined the number of persons needed to screen to identify one TB case, and the number of cases identified that linked to clinic and completed TB treatment.

RESULTS

Of 36,785 adults enumerated in 7 communities, 27,214 (74%) attended CHCs, and HIV testing uptake was >99%, with 941 (3.5%) HIV-infected adults identified. Five thousand seven hundred eighty-six adults (21%) reported cough and 2876 (11%) reported cough >2 weeks. Staff obtained sputum in 1099/2876 (38%) participants with prolonged cough and identified 10 adults with AFB-positive sputum; 9 new diagnoses and 1 known case already under treatment. The number needed to screen to identify one new TB case was 3024 adults overall: 320 adults with prolonged cough and 80 HIV-infected adults with prolonged cough. All 9 newly diagnosed AFB+ participants were linked to TB care within 2 weeks and were initiated TB treatment.

CONCLUSIONS

In a rural Ugandan setting, TB screening as an adjunct to large-scale mobile HIV testing campaigns provides an opportunity to increase TB case detection.

Clinical Impact of Nucleic Acid Amplification Testing in the Diagnosis of Mycobacterium Tuberculosis: A 10-Year Longitudinal Study

BACKGROUND

Nucleic acid amplification (NAA) testing for Mycobacterium tuberculosis (MTB) offers improved diagnostic accuracy, compared with smear microscopy, in differentiating MTB from other mycobacteria. We aimed to evaluate the reliability and projected impact of NAA testing in patients with acid-fast bacilli (AFB) smear-positive respiratory samples.

METHODS

We identified a retrospective cohort of all patients with AFB smear-positive respiratory specimens at Henry Ford Hospital from January 1, 2001 through December 31, 2011. We examined the association between patients' sociodemographic factors and clinical comorbidities with the likelihood of being diagnosed with MTB. We evaluated the projected change in duration of airborne isolation and unnecessary MTB treatment with introducing NAA testing into clinical decision making for AFB smear-positive patients.

RESULTS

One hundred thirty patients had AFB smear-positive respiratory specimens, 80 of these patients had a positive NAA test result, and 82 patients grew MTB on culture. Nucleic acid amplification testing had a sensitivity and specificity of 97.6% and 100%, respectively. Integrating NAA testing into clinical decision making for patients with AFB-positive smears was associated with a significantly shorter time in airborne isolation (6.0 ± 7.6 vs 23.1 ± 38.0, P < .001) and 9.5 ± 11.32 fewer days of unnecessary MTB treatment in patients with negative NAA test.

CONCLUSIONS

Nucleic acid amplification testing provided a rapid and accurate test in the diagnosis of MTB while significantly reducing the duration of isolation and unnecessary medications in patients with negative NAA test.

Identifying barriers to and facilitators of tuberculosis contact investigation in Kampala, Uganda: a behavioral approach

BACKGROUND

The World Health Organization recommends routine household tuberculosis contact investigation in high-burden countries but adoption has been limited. We sought to identify barriers to and facilitators of TB contact investigation during its introduction in Kampala, Uganda.

METHODS

We collected cross-sectional qualitative data through focus group discussions and interviews with stakeholders, addressing three core activities of contact investigation: arranging household screening visits through index TB patients, visiting households to screen contacts and refer them to clinics, and evaluating at-risk contacts coming to clinics. We analyzed the data using a validated theory of behavior change, the Capability, Opportunity, and Motivation determine Behavior (COM-B) model, and sought to identify targeted interventions using the related Behavior Change Wheel implementation framework.

RESULTS

We led seven focus-group discussions with 61 health-care workers, two with 21 lay health workers (LHWs), and one with four household contacts of newly diagnosed TB patients. We, in addition, performed 32 interviews with household contacts from 14 households of newly diagnosed TB patients. Commonly noted barriers included stigma, limited knowledge about TB among contacts, insufficient time and space in clinics for counselling, mistrust of health-center staff among index patients and contacts, and high travel costs for LHWs and contacts. The most important facilitators identified were the personalized and enabling services provided by LHWs. We identified education, persuasion, enablement, modeling of health-positive behaviors, incentivization, and restructuring of the service environment as relevant intervention functions with potential to alleviate barriers to and enhance facilitators of TB contact investigation.

CONCLUSIONS

The use of a behavioral theory and a validated implementation framework provided a comprehensive approach for systematically identifying barriers to and facilitators of TB contact investigation. The behavioral determinants identified here may be useful in tailoring interventions to improve implementation of contact investigation in Kampala and other similar urban settings.

Diagnostics for pulmonary tuberculosis

Tuberculosis (TB) remains a leading cause of human suffering and mortality despite decades of effective treatment being available. Accurate and timely diagnosis remains an unmet goal. The HIV epidemic has also led to new challenges in the diagnosis of TB. Several new developments in TB diagnostics have the potential to positively influence the global campaign against TB. We aim to review the performance of both established as well as new diagnostics for pulmonary TB in adults, and discuss the ongoing challenges.

What a difference a day makes: same-day vs. 2-day sputum smear microscopy for diagnosing tuberculosis

Setting: Nine district-level microscopy centres in Assam and Tripura, India. Objective: Same-day sputum microscopy is now recommended for tuberculosis (TB) diagnosis. We compared this method against the conventional 2-day approach in routine programmatic settings. Methods: During October-December 2012, all adult presumptive TB patients were requested to provide three sputum samples (one at the initial visit, the second 1 h after the first sample, and the third the next morning) for examination by Ziehl-Neelsen smear microscopy. Detection of acid-fast bacilli with any sample was diagnostic. The first and second spot sample comprised the same-day approach, and the first spot sample and next-day sample comprised the 2-day approach. Results: Of 2168 presumptive TB patients, 403 (18.6%) were smear-positive according to the same-day method compared to 427 (19.7%) by the 2-day method (McNemar's test, P < 0.001). Of the total 429 TB patients, 26 (6.1%) were missed by the same-day method and 2 (0.5%) by the 2-day method. Conclusion: Same-day specimen collection for microscopy missed more TB than 2-day collection. In India, missing cases by using same-day microscopy would translate into a considerable absolute number, hindering TB control efforts. We question the indiscriminate switch to same-day diagnosis in settings where patients reliably return for testing the next day.

Official American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America Clinical Practice Guidelines: Treatment of Drug-Susceptible Tuberculosis

The American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America jointly sponsored the development of this guideline for the treatment of drug-susceptible tuberculosis, which is also endorsed by the European Respiratory Society and the US National Tuberculosis Controllers Association. Representatives from the American Academy of Pediatrics, the Canadian Thoracic Society, the International Union Against Tuberculosis and Lung Disease, and the World Health Organization also participated in the development of the guideline. This guideline provides recommendations on the clinical and public health management of tuberculosis in children and adults in settings in which mycobacterial cultures, molecular and phenotypic drug susceptibility tests, and radiographic studies, among other diagnostic tools, are available on a routine basis. For all recommendations, literature reviews were performed, followed by discussion by an expert committee according to the Grading of Recommendations, Assessment, Development and Evaluation methodology. Given the public health implications of prompt diagnosis and effective management of tuberculosis, empiric multidrug treatment is initiated in almost all situations in which active tuberculosis is suspected. Additional characteristics such as presence of comorbidities, severity of disease, and response to treatment influence management decisions. Specific recommendations on the use of case management strategies (including directly observed therapy), regimen and dosing selection in adults and children (daily vs intermittent), treatment of tuberculosis in the presence of HIV infection (duration of tuberculosis treatment and timing of initiation of antiretroviral therapy), as well as treatment of extrapulmonary disease (central nervous system, pericardial among other sites) are provided. The development of more potent and better-tolerated drug regimens, optimization of drug exposure for the component drugs, optimal management of tuberculosis in special populations, identification of accurate biomarkers of treatment effect, and the assessment of new strategies for implementing regimens in the field remain key priority areas for research. See the full-text online version of the document for detailed discussion of the management of tuberculosis and recommendations for practice.

Pathways and costs of care for patients with tuberculosis symptoms in rural Uganda

SETTING

Six district-level government health centers in rural Uganda and the surrounding communities.

OBJECTIVE

To determine pathways to care and associated costs for patients with chronic cough referred for tuberculosis (TB) evaluation in Uganda.

DESIGN

We conducted a cross-sectional study, surveying 64 patients presenting with chronic cough and undergoing first-time sputum evaluation at government clinics. We also surveyed a random sample of 114 individuals with chronic cough in surrounding communities. We collected information on previous health visits for the cough as well as costs associated with the current visit.

RESULTS

Eighty per cent of clinic patients had previously sought care for their cough, with a median of three previous visits (range 0-32, interquartile range [IQR] 2-5). Most (n = 203, 88%) visits were to a health facility that did not provide TB microscopy services, and the majority occurred in the private sector. The cost of seeking care for the current visit alone represented 28.8% (IQR 9.1-109.5) of the patients' median monthly household income.

CONCLUSION

Most patients seek health care for chronic cough, but do so first in the private sector. Engagement of the private sector and streamlining TB diagnostic evaluation are critical for improving case detection and meeting global TB elimination targets.

Utility of QuantiFERON-TB Gold In-Tube assay in adult, pulmonary and extrapulmonary, active tuberculosis diagnosis

BACKGROUND

Tuberculosis remains a public health problem in France and the diagnosis of tuberculosis disease (TB) is sometimes difficult. The aim of this study was to analyse the contribution of the QuantiFERON-TB Gold In-Tube assay (QFT-GIT) to TB diagnosis.

METHODS

Sixty patients hospitalized with TB, for whom a QFT-GIT assay had been performed between June 2008 and June 2011 at the University Hospital of Bondy in the north-east of Paris, were identified retrospectively. Clinical and laboratory data were collected. The sensitivity, specificity, predictive values, and likelihood ratios of the QFT-GIT were all calculated. Furthermore, the characteristics of patients testing positive were compared to those of patients testing negative, as well as the QFT-GIT values according to several different factors.

RESULTS

The sensitivity of the QFT-GIT was 85% (95% confidence interval (CI) 0.73-0.92) and specificity was 73.3% (95% CI 0.68-0.78). The positive predictive value was 39.5% and the negative predictive value was 97.3%. The positive and negative likelihood ratios were 3.2 and 0.20, respectively. The prevalence of TB in this population was 15% (pre-test probability). After a positive test result, the probability of TB increased to 40% (post-positive probability test); after a negative test result, it decreased to 4.5% (post-negative probability test). The combination of the QFT-GIT test with the tuberculin skin test brought no significant improvement in sensitivity. Factors significantly associated with a negative QFT-GIT result included older age, high C-reactive protein, a low lymphocyte count, and immunosuppressant intake. The test value in quantitative terms was significantly higher in those with lymph node TB than in those with pulmonary TB, and in younger patients (<40 years) than in older patients (>40 years old).

CONCLUSION

On its own, QFT-GIT is an insufficient tool to confirm the diagnosis of TB disease. However, it may form part of an ensemble of tools in combination with clinical, biological, and radiological assessments.

Use of string test and stool specimens to diagnose pulmonary tuberculosis

Background

The Xpert MTB/RIF (MTB/RIF) test has advanced the field of tuberculosis (TB) diagnostics; however, depending on age and HIV status, 10–85% of individuals with presumed pulmonary TB (PTB) are unable to produce sputum.

Methods

The feasibility of using MTB/RIF and culture on stool and string test specimens from 13 adult patients with presumed PTB was studied.

Results

The string test was well tolerated with a median Wong Baker Faces score of 2. The string test had 100% sensitivity and specificity by MTB/RIF and 87.5% sensitivity and 100% specificity by culture. In stool, Mycobacterium tuberculosis DNA was detected in all cases of culture-confirmed PTB.

Conclusion

The string test and stool provide diagnostic specimens that warrant further investigation.

Transformative tools for tackling tuberculosis

The world is in need of more effective approaches to controlling tuberculosis. The development of improved control strategies has been hampered by deficiencies in the tools available for detecting Mycobacterium tuberculosis and defining the dynamic consequences of the interaction of M. tuberculosis with its human host. Key needs include a highly sensitive, specific nonsputum diagnostic; biomarkers predictive of responses to therapy; correlates of risk for disease development; and host response-independent markers of M. tuberculosis infection. Tools able to sensitively detect and quantify total body M. tuberculosis burden might well be transformative across many needed use cases. Here, we review the current state of the field, paying particular attention to needed changes in experimental paradigms that would facilitate the discovery, validation, and development of such tools.

Investigating Barriers to Tuberculosis Evaluation in Uganda Using Geographic Information Systems

Reducing geographic barriers to tuberculosis (TB) care is a priority in high-burden countries where patients frequently initiate, but do not complete, the multi-day TB evaluation process. Using routine cross-sectional study from six primary-health clinics in rural Uganda from 2009 to 2012, we explored whether geographic barriers affect completion of TB evaluation among adults with unexplained chronic cough. We measured distance from home parish to health center and calculated individual travel time using a geographic information systems technique incorporating roads, land cover, and slope, and measured its association with completion of TB evaluation. In 264,511 patient encounters, 4,640 adults (1.8%) had sputum smear microscopy ordered; 2,783 (60%) completed TB evaluation. Median travel time was 68 minutes for patients with TB examination ordered compared with 60 minutes without (P < 0.010). Travel time differed between those who did and did not complete TB evaluation at only one of six clinics, whereas distance to care did not differ at any of them. Neither distance nor travel time predicted completion of TB evaluation in rural Uganda, although limited detail in road and village maps restricted full implementation of these mapping techniques. Better data are needed on geographic barriers to access clinics offering TB services to improve TB diagnosis.

Diagnosis of pulmonary tuberculosis: recent advances and diagnostic algorithms

Pulmonary tuberculosis (TB) persists as a great public health problem in Korea. Increases in the overall age of the population and the rise of drug-resistant TB have reinforced the need for rapid diagnostic improvements and new modalities to detect TB and drug-resistant TB, as well as to improve TB control. Standard guidelines and recent advances for diagnosing pulmonary TB are summarized in this article. An early and accurate diagnosis of pulmonary TB should be established using chest X-ray, sputum microscopy, culture in both liquid and solid media, and nucleic acid amplification. Chest computed tomography, histopathological examination of biopsy samples, and new molecular diagnostic tests can be used for earlier and improved diagnoses, especially in patients with smear-negative pulmonary TB or clinically-diagnosed TB and drug-resistant TB.

Diagnostic yield of sputum microbiological analysis in the diagnosis of pulmonary tuberculosis in a period of 10 years

INTRODUCTION

Pulmonary tuberculosis (TB) requires an early diagnosis for prompt introduction of treatment and prevention of transmission. Definitive diagnosis is obtained by microbiological culture and identification of Mycobacterium tuberculosis in respiratory specimens, mostly sputum samples.

MATERIALS AND METHODS

Retrospective data analysis of all patients suspected of pulmonary TB that submitted three consecutive sputum samples to the Pulmonology Diagnostic Center (PDC) Laboratory between 2004 and 2013. Extrapulmonary TB cases were excluded. Four microbiological analyses were executed on each specimen: two smears with Ziehl-Neelsen staining, direct and concentrate; and two culture examinations, one in liquid and one in solid medium. Statistical analysis was performed by SPSS.

RESULTS

A total of 694 patients were enrolled in this study (65% men, mean age 48.5±18.6 years, 97% Portuguese), most of them exhibiting TB-related complaints. Pulmonary TB was diagnosed in 41% of the patients; 54% had non-specific radiological changes and 34% had pulmonary cavitation. The cumulative sensitivity rates of each of the three smears were 24.6%, 27.7% and 28.8% for concentrated samples and 19.3%, 20.4% and 22.5% for direct samples. The cumulative sensitivities of sputum culture were 33.3%, 37.9% and 41.8% for solid medium, and 43.9%, 51.6% and 55.4% for liquid medium. Pondering all forms of microbiological analysis, the cumulative sensitivities of each sample were 51.2%, 59.6% and 63.2%. There was an incremental yield of 8.4% for the second specimen and 3.5% for the third specimen. All sensitivity rates were higher among patients with pulmonary cavitation.

CONCLUSIONS

This study showed an incremental yield with more than one sputum sample. However, overall sensitivity remained low, suggesting a need for new diagnostic strategies and novel and better diagnostic tools.

Sputum induction is a safe procedure to use in prisoners and MGIT is the best culture method to diagnose tuberculosis in prisons: a cohort study

OBJECTIVES

To evaluate the concordance and safety of induced sputum (IS) and spontaneous sputum (SS), and estimate concordance and time to detection of M. tuberculosis between Lowenstein-Jensen (LJ), thin-layer agar (TLA), and the Mycobacteria Growth Indicator Tube system (MGIT).

METHODS

This was a cohort study. Prisoners with pulmonary tuberculosis (PTB) were followed for 2 years. At baseline and every follow-up visit, three sputum samples were taken on consecutive days (one IS and two SS) and adverse events occurring before, during, and 30 min after IS were registered. All sputum samples were stained with auramine and cultured in LJ, TLA (to test resistance), and MGIT.

RESULTS

Five hundred eighty-six IS and 532 SS were performed on 64 PTB patients. Breathlessness (1.6%), cough (1.2%), hemoptysis (0.3%), and cyanosis (0.2%) were the only complications. Concordance between IS and SS was 0.78 (95% confidence interval 0.69-0.87); 11 positive cultures from IS samples were negative in SS, and 11 positive cultures from SS samples were negative in IS. One hundred seventy-eight cultures were positive by any technique: MGIT 95%, LJ 73%, and TLA 57%. Time to detection of M. tuberculosis in LJ, TLA, and MGIT was 31, 18, and 11 days, respectively.

CONCLUSIONS

The IS procedure is safe in prisons. The MGIT system is better and faster than LJ and TLA in the diagnosis of M. tuberculosis.

Evaluation and comparison of molecular and conventional diagnostic tests for detecting tuberculosis in Korea, 2013

Objectives

A fast and accurate diagnosis is necessary to control and eliminate tuberculosis (TB). In Korea, TB continues to be a serious public health problem. In this study, diagnostic tests on clinical samples from patients suspected to have TB were performed and the sensitivity and specificity of the various techniques were compared. The main objective of the study was to compare various diagnostic tests and evaluate their sensitivity and specificity for detecting tuberculosis.

Methods

From January 2013 to December 2013, 170,240 clinical samples from patients suspected to have TB were tested with smear microscopy, acid-fast bacilli culture, and real-time polymerase chain reaction (PCR). The test results were compared and data were analyzed.

Results

A total of 8216 cultures tested positive for TB (positive detection rate, 4.8%). The contamination rate in the culture was 0.6% and the isolation rate of nontuberculous mycobacteria was 1.0%. The sensitivity and specificity of smear microscopy were 56.8% and 99.6%, respectively. The concordance rate between the solid and liquid cultures was 92.8%. Mycobacterium isolates were not detected in 0.4% of the cases in the liquid culture, whereas no Mycobacterium isolates were detected in 6.8% of the cases in the solid culture. The sensitivity and specificity of real-time PCR for the solid culture were 97.2% and 72.4%, respectively, whereas the corresponding data for the liquid culture were 93.5% and 97.2%.

Conclusion

The study results can be used to improve existing TB diagnosis procedure as well as for comparing the effectiveness of the assay tests used for detecting Mycobacterium tuberculosis isolates.

Improving the estimation of the tuberculosis burden in India

Although India is considered to be the country with the greatest tuberculosis burden, estimates of the disease’s incidence, prevalence and mortality in India rely on sparse data with substantial uncertainty. The relevant available data are less reliable than those from countries that have recently improved systems for case reporting or recently invested in national surveys of tuberculosis prevalence. We explored ways to improve the estimation of the tuberculosis burden in India. We focused on case notification data – among the most reliable data available – and ways to investigate the associated level of underreporting, as well as the need for a national tuberculosis prevalence survey. We discuss several recent developments – i.e. changes in national policies relating to tuberculosis, World Health Organization guidelines for the investigation of the disease, and a rapid diagnostic test – that should improve data collection for the estimation of the tuberculosis burden in India and elsewhere. We recommend the implementation of an inventory study in India to assess the underreporting of tuberculosis cases, as well as a national survey of tuberculosis prevalence. A national assessment of drug resistance in Indian strains of Mycobacterium tuberculosis should also be considered. The results of such studies will be vital for the accurate monitoring of tuberculosis control efforts in India and globally.

Tuberculosis in tropical areas and immigrants

About 95% of cases and 98% of deaths due to tuberculosis (TB) occur in tropical countries while, in temperate low incidence countries, a disproportionate portion of TB cases is diagnosed in immigrants. Urbanization, poverty, poor housing conditions and ventilation, poor nutritional status, low education level, the HIV co-epidemic, the growing impact of chronic conditions such as diabetes are the main determinants of the current TB epidemiology in tropical areas. TB care in these contests is complicated by several barriers such as geographical accessibility, educational, cultural, sociopsychological and gender issues. High quality microbiological and radiological facilities are not widely available, and erratic supply of anti-TB drugs may affect tropical areas from time to time. Nevertheless in recent years, TB control programs reached major achievements in tropical countries as demonstrated by several indicators. Migrants have a high risk of acquire TB before migration. Moreover, after migration, they are exposed to additional risk factors for acquiring or reactivating TB infection, such as poverty, stressful living conditions, social inequalities, overcrowded housing, malnutrition, substance abuse, and limited access to health care. TB mass screening programs for migrants have been implemented in low endemic countries but present several limitations. Screening programs should not represent a stand-alone intervention, but a component of a wider approach integrated with other healthcare activities to ensure the health of migrants.

Comparing same day sputum microscopy with conventional sputum microscopy for the diagnosis of tuberculosis--Chhattisgarh, India

BACKGROUND

The World Health Organization (WHO) recommends same day sputum microscopy (spot-spot) in preference to conventional strategy (spot-morning) for the diagnosis of smear positive tuberculosis with the view that completing diagnosis on a single day may be more convenient to the patients and reduce pre-treatment losses to follow-up.

METHODS

We conducted a cross-sectional study in seven selected district level hospitals of Chhattisgarh State, India. During October 2012 - March 2013, two sputum specimens (spot-early morning) were collected from consecutively enrolled adult (≥ 18 years) presumptive TB patients as per current national guidelines. In addition, a second sample was collected (one hour after the collection of first spot sample) from the same patients. All the samples were examined by ziehl-Neelsen (ZN) microscopy. McNemar's test was used to compare statistical differences in the proportion smear positive between the two approaches (spot-spot versus spot-morning).

RESULTS

Of 2551 presumptive TB patients, 69% were male. All patients provided the first spot specimen, 2361 (93%) provided the second spot specimen, and 2435 (96%) provided an early morning specimen. 72% of specimens were mucopurulent in conventional strategy as compared to 60% in same day strategy. The proportion of smear-positive patients diagnosed by same day microscopy was 14%, as compared to 17% by the conventional method (p<0.001). A total of 73 (16.9%) potential cases were missed by the same day method compared to only 2 (0.5%) by the conventional method.

CONCLUSION

Same-day microscopy method missed 17% of smear-positive cases and contrary to prior perception, did not increase the proportion of suspects providing the second sample. These findings call for an urgent need to revisit the WHO recommendation of switching to same-day diagnosis over the current policy.