Performance evaluation of truenat test for detection of pulmonary tuberculosis among HIV symptomatic patients at Lira Regional Referral Hospital

Abstract

Background: About a quarter of the world’s population has been infected with Mycobacterium tuberculosis, in immune compromised people like in HIV- infected persons, the risk of developing tuberculosis is 22 times higher. With advancement in technology, a new molecular tuberculosis diagnostic tool named Truenat has been developed recently by Molbio Diagnostics, Bangalore, India. Objective: This study aimed to determine the accuracy of the Truenat test and the ease of use in the detection of pulmonary tuberculosis among HIV symptomatic patients attending ART clinic at Lira Regional Referral Hospital. Methods: It was a cross sectional study where 243 patients attending ART clinic at Lira Regional Referral Hospital who are asymptomatic of tuberculosis were consented and recruited into the study. Operating under a safety cabinet, the sample was divided into three portions. The first portion was used for Gene xpert, second portion referred for Truenat test in Amach H/C IV in Lira while the remaining portion was referred to National tuberculosis reference laboratory for Culture using Lowenstein Jensen and Drug Susceptibility Test. Lowenstein Jensen culture media was used as the referenced standards (gold standard). Operational feasibility assessment data through interview of the study laboratory personnel were also collected and presented as percentages. Results: In this study of 243 people who are HIV seropositive with symptoms of TB conducted in Lira Regional Referral Hospital, Uganda, the Truenat MTB Plus assay had a sensitivity of 100%, (95%CI; 100%) to detect TB among those with culture-positive TB. In this evaluation, the overall specificity of the Truenat MTB Plus assay was 99.1%; (95% CI, 97.9 to 100%); 2 of 243 participants with culture-negative results for TB had a result of MTB detected on the Truenat MTB Plus assay. For the purpose of the diagnostic accuracy evaluation, these results are considered as false positives compared to the reference standard of culture. From end users; the Truenat is a simple molecular test which is an alternative for Genexpert that requires solar and electricity for charging and this makes it suitable for peripheral laboratory settings with limited resources. Conclusion: The findings reported provide support for the use of the Truenat as a test with acceptable sensitivity and specificity for diagnosis of pulmonary tuberculosis compared to Genexpert ultra and culture, including people living with HIV, as recently recommended by the WHO.