BackgroundLight-emitting diode fluorescence microscopy (LED-FM) has been shown to be more sensitive than conventional bright field microscopy using Ziehl-Neelsen (ZN) stain in detecting sputum smear positive tuberculosis in controlled laboratory conditions. In 2012, Auramine O staining based LED-FM replaced conventional ZN microscopy in 200 designated microscopy centres (DMC) of medical colleges operating in collaboration with India’s Revised National Tuberculosis Control Programme. We aimed to assess the impact of introduction of LED-FM services on sputum smear positive case detection under program conditions.MethodsThis was a before and after comparison study. In 15 randomly selected medical college DMCs, all presumptive TB patients who underwent sputum smear examination in the years 2011 (before LED-FM) and 2012 (after LED-FM) were compared. An additional 15 comparable DMCs that implemented conventional ZN sputum smear microscopy were also selected for comparison between 2011 and 2012.ResultsThe proportion of presumptive TB patients (PTP)found sputum smear positive increased by 30%- from 13.6% (3432/25159) in 2011 to 17.8% (4706/26426) in 2012 (P value <0.01) in the sites that implemented LED-FM microscopy, whereas in DMCs where the ZN staining procedure is followed the proportion of sputum smear positive had remained unchanged (13.0%versus 12.6%;P value0.31).ConclusionUse of LED-FM significantly increased the proportion of smear positive cases among presumptive TB patients under routine program conditions in high workload laboratories. The study provides operational evidence needed to scale-up the use of LED-FM in similar settings in India and beyond.

LED FM is a cost-effective intervention for detecting TB cases in India at high-workload medical college settings.

BackgroundIn India, since July 2012, at designated Microscopy Centers (DMCs) in 200 medical colleges, sputum smear examination for tuberculosis bacilli changed from Ziehl Neelsen (ZN) method to auramine based Light Emitting Diode Fluorescent Microscopy (LED-FM) method. We assessed the additional yield of smear positives among patients undergoing follow-up sputum examination during TB treatment before and after deploying LED-FM.MethodsThis was a before and after comparison study in eight conveniently selected medical college DMCs across North India. We extracted data from TB laboratory registers on number of TB patients examined for follow-up and their smear microscopy results including the grades by ZN (before; July–December 2011) and LED-FM (after; July–December 2012) and compared them.ResultsAltogether, 2868 TB patients were examined by LED-FM and 2740 were examined by ZN during follow-up. LED-FM increased the proportion of follow-up smear positives from 5.0 % (n = 136) to 7.4 % (n = 213) with an additional yield of 77 follow-up smear-positives—with the highest increase in smears graded scanty (2.6 vs 1.2 %) (p value <0.05).ConclusionsSince all smear positives during follow-up are considered ‘presumptive multidrug resistant (MDR)-TB patients’ in India, introduction of LED-FM would result in additional number of patients eligible for MDR-TB testing, which would have otherwise been missed by ZN.

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