Evidence Supports TB Test, So what Now?

Cohen, Danielle B.; Corbett, Elizabeth L.

doi:10.1002/14651858.ed000051

Cited by 2 publications

(2 citation statements)

References 10 publications

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“…These results should be confirmed in another study but they are encouraging, taking into consideration the short time to positivity of the RETAp, compared with LJ medium culture (median, 10 days versus 25 days). 32). Culture methods in general cannot compare with this molecular test in terms of the time to obtain results and the simplicity of use.…”

Section: Discussionmentioning

confidence: 99%

Use of Colorimetric Culture Methods for Detection of Mycobacterium tuberculosis Complex Isolates from Sputum Samples in Resource-Limited Settings

et al. 2013

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e Despite recent advances, tuberculosis (TB) diagnosis remains imperfect in resource-limited settings due to its complexity and costs, poor sensitivity of available tests, or long times to reporting. We present a report on the use of colorimetric methods, based on the detection of mycobacterial growth using colorimetric indicators, for the detection of Mycobacterium tuberculosis in sputum specimens. We evaluated the nitrate reductase assay (NRA), a modified NRA using para-nitrobenzoic acid (PNB) (NRAp), and the resazurin tube assay using PNB (RETAp) to differentiate tuberculous and nontuberculous mycobacteria. The performances were assessed at days 18 and 28 using mycobacterium growth indicator tube (MGIT) and Löwenstein-Jensen (LJ) medium culture methods as the reference standards. We enrolled 690 adults with suspected pulmonary tuberculosis from a regional referral hospital in Uganda between March 2010 and June 2011. At day 18, the sensitivities and specificities were 84.6% and 90.0% for the NRA, 84.1% and 92.6% for the NRAp, and 71.2% and 99.3% for the RETAp, respectively. At day 28, the sensitivity of the RETAp increased to 82.6%. Among smear-negative patients with suspected TB, sensitivities at day 28 were 64.7% for the NRA, 61.3% for the NRAp, and 50% for the RETAp. Contamination rates were found to be 5.4% for the NRA and 6.7% for the RETAp, compared with 22.1% for LJ medium culture and 20.4% for MGIT culture. The median times to positivity were 10, 7, and 25 days for colorimetric methods, MGIT culture, and LJ medium culture,respectively. Whereas the low specificity of the NRA/NRAp precludes it from being used for TB diagnosis, the RETAp might provide an alternative to LJ medium culture to decrease the time to culture results in resource-poor settings.

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Section: Discussionmentioning

confidence: 99%

Use of Colorimetric Culture Methods for Detection of Mycobacterium tuberculosis Complex Isolates from Sputum Samples in Resource-Limited Settings

et al. 2013

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“…Since then, unprecedented efforts have been made by National Tuberculosis Programs (NTPs) across the globe to scale up these tests and included them as part of the routine TB diagnostic algorithms [9][10][11]. These NAATs have proven to have high accuracy, and research has increasingly focused on studying their actual clinical impact [10,[12][13][14][15][16]. While there are systematic reviews on the diagnostic accuracy of Xpert and LPAs [6,17,18], and others that separately describe diagnostic and treatment delays experienced by TB patients [19], no study has summarized the impact of NAATs on reducing time delays in diagnosis and treatment of TB.…”

Section: Introductionmentioning

confidence: 99%

Impact of molecular diagnostic tests on diagnostic and treatment delays in tuberculosis: a systematic review and meta-analysis

et al. 2022

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Background Countries with high TB burden have expanded access to molecular diagnostic tests. However, their impact on reducing delays in TB diagnosis and treatment has not been assessed. Our primary aim was to summarize the quantitative evidence on the impact of nucleic acid amplification tests (NAAT) on diagnostic and treatment delays compared to that of the standard of care for drug-sensitive and drug-resistant tuberculosis (DS-TB and DR-TB). Methods We searched MEDLINE, EMBASE, Web of Science, and the Global Health databases (from their inception to October 12, 2020) and extracted time delay data for each test. We then analysed the diagnostic and treatment initiation delay separately for DS-TB and DR-TB by comparing smear vs Xpert for DS-TB and culture drug sensitivity testing (DST) vs line probe assay (LPA) for DR-TB. We conducted random effects meta-analyses of differences of the medians to quantify the difference in diagnostic and treatment initiation delay, and we investigated heterogeneity in effect estimates based on the period the test was used in, empiric treatment rate, HIV prevalence, healthcare level, and study design. We also evaluated methodological differences in assessing time delays. Results A total of 45 studies were included in this review (DS = 26; DR = 20). We found considerable heterogeneity in the definition and reporting of time delays across the studies. For DS-TB, the use of Xpert reduced diagnostic delay by 1.79 days (95% CI − 0.27 to 3.85) and treatment initiation delay by 2.55 days (95% CI 0.54–4.56) in comparison to sputum microscopy. For DR-TB, use of LPAs reduced diagnostic delay by 40.09 days (95% CI 26.82–53.37) and treatment initiation delay by 45.32 days (95% CI 30.27–60.37) in comparison to any culture DST methods. Conclusions Our findings indicate that the use of World Health Organization recommended diagnostics for TB reduced delays in diagnosing and initiating TB treatment. Future studies evaluating performance and impact of diagnostics should consider reporting time delay estimates based on the standardized reporting framework.

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Evidence Supports TB Test, So what Now?

Cited by 2 publications

References 10 publications

Use of Colorimetric Culture Methods for Detection of Mycobacterium tuberculosis Complex Isolates from Sputum Samples in Resource-Limited Settings

Use of Colorimetric Culture Methods for Detection of Mycobacterium tuberculosis Complex Isolates from Sputum Samples in Resource-Limited Settings

Impact of molecular diagnostic tests on diagnostic and treatment delays in tuberculosis: a systematic review and meta-analysis

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