Tuberculosis. Diagnosis Goes Faster with Microscopic Observation

TB Diagnosis Goes Faster with Microscopic Observation
Use of the microscopic-observation drug-susceptibility (MODS) assay resulted in faster and more sensitive diagnosis of TB and multidrug-resistant TB than conventional methods in a study reported in today's New England Journal of Medicine.
Researchers in Peru analyzed roughly 3700 sputum samples from some 2000 patients with suspected TB, multidrug-resistant TB, or established HIV infection.
Median turnaround time for culture growth and drug-susceptibility testing was 1 week on both counts for MODS, compared with about 2 weeks for culture growth and about 3 weeks for drug susceptibility with the quicker of the other two methods tested. The MODS assay was also significantly more sensitive than the other two methods for both diagnosing TB and detecting drug susceptibility.
Writing in Journal Watch Infectious Diseases, associate editor Daniel J. Diekema concludes that the MODS assay is "an affordable, rapid method for culture-based detection of TB," including multidrug-resistant TB. However, he agrees with two editorialists that developing labs with adequate biosafety standards to perform this test remains a challenge. This is a particular problem in resource-poor countries.
NEJM article (Free)
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Journal Watch Infectious Diseases summary (Free)