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A new interesting article has been published in J Clin Microbiol. 2019 Jul 3. pii: JCM.00614-19. doi: 10.1128/JCM.00614-19. and titled:

Same day tools, including Xpert Ultra and unstimulated IFN-γ, for the rapid diagnosis of pleural tuberculosis – a prospective observational study.

Authors of this article are:

Meldau R, Randall P, Pooran A, Limberis J, Makambwa E, Dhansay M, Esmail A, Dheda K.

A summary of the article is shown below:

Introduction:The diagnosis of pleural tuberculosis (TB) is problematic. The comparative performance of newer same day tools for pleural TB including Xpert MTB/RIF Ultra (ULTRA) has, hitherto, not been comprehensively been studied.Methods:Adenosine deaminase (ADA), Inter-Gam Ultrasensitive Rapid Immuno-suspension Assay (IRISA-TB), Xpert MTB/RIF, and ULTRA performance outcomes were evaluated in pleural fluid samples from 149 patients with suspected pleural TB. The reference standard was culture positivity (fluid, biopsy or sputum) and/or pleural biopsy histopathology (definite-TB). Those with non-TB were microbiologically test negative and were not initiated on anti-TB treatment. To determine the effect of sample concentration, 65 samples underwent pelleting by centrifugation followed by conventional Xpert MTB/RIF and ULTRA.Results:Of the 149 patients, 49 had definite-TB, 16 probable-TB (not definite but treated for TB) and 84 non-TB. ULTRA sensitivity (95% CI) and specificity was similar to Xpert MTB/RIF [37.5% (25.3-51.2) versus 28.6% (15.9-41.2)] and [98.8% (96.5-100) versus 98.8% (96.5-100)], respectively. Centrifugation did not significantly improve ULTRA sensitivity (29.5% vs. 31.3%, respectively). Adenosine deaminase and IRISA-TB sensitivity was 84.4% (73.9 – 95.0) and 89.8% (81.3- 98.3), respectively. However, IRISA-TB demonstrated significantly better specificity [96.4% vs. 87.5% (p= 0.034)], positive-predictive value [93.6% vs. 80.9 (p= 0.028)] and positive-likelihood ratio [25.1 vs. 6.8 (p= 0.032)] than ADA.Conclusion:Xpert ULTRA has poor sensitivity for the diagnosis of pleural TB. Alternative assays (ADA and IRISA-TB) are significantly more sensitive, with IRISA-TB demonstrating a higher specificity and rule-in value compared to ADA in this high TB and HIV-endemic setting.Copyright © 2019 Meldau et al.

Check out the article’s website on Pubmed for more information:

[link-preview url=https://www.ncbi.nlm.nih.gov/pubmed/31270183 forceshot=true]

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