In TB detection, smear microscopy’s share still holds sway

“Many of the patients enrolled in the trial had either not undergone any testing or not completed the long-duration treatment… Most of the patients enrolled in the trial had extensive disease affecting both their lungs,” Dr. C Padmapriyadarsini, Director of the Chennai-based National Institute for Research in Tuberculosis and the trial coordinator of the modified BPaL regimen, told The Hindu. In 2020, India renamed RNTCP as the National TB Elimination Program to underscore India’s goal to eliminate TB by 2025 As per the National Strategic Plan for TB Elimination 2017-2025, the number of smear microscopy tests should have reduced from over 9.1 million in 2015 to 5.8 million in 2022, and molecular tests increased from 40,000 in 2015 to over 13.4 million in 2022 But in 2022, 77% of all presumptive TB cases were examined using smear microscopy and just 23% with a molecular test Sputum sear microscopy has about 50% sensitivity and cannot identify rifampicin resistance, leading to many missed cases As per the 2014 WHO guidelines, Genexpert molecular test should be used as an initial diagnostic test The National TB prevalence survey report 2019-2021 says nearly 64% in India did not get tested for TB Patients with sub-clinical TB may show no symptoms but may be infectious, making it harder to achieve the 2025 goal Worse, even when people finally get tested for TB, sputum smear microscopy with about 50% sensitivity has been used for diagnosis in a majority of the cases in India, thus leading to a huge number of missed TB cases. Even in 2015, the Joint monitoring mission report had criticised the national TB programme for heavily relying on smear microscopy and for the “slow uptake of the new molecular test”. As per the National Strategic Plan for TB Elimination 2017-2025 report, the number of presumptive TB patients to be offered sputum smear microscopy should have reduced from over 9.1 million in 2015 to 5.8 million in 2022, while the number of molecular tests should have increased from 40,000 in 2015 to over 13.4 million in 2022. As per the India TB report 2023, even last year, 77% of presumptive TB cases were examined using smear microscopy and just 23% with a molecular test.