A profile on the Truenat assays for the detection of pulmonary tuberculosis and rifampicin resistance.

内容摘要

Early diagnosis and treatment initiation are essential to prevent ongoing tuberculosis (TB) transmission and reduce the disease burden. Smear microscopy, which is widely used test for diagnosis, has limited sensitivity and does not detect rifampicin resistance. Truenat is a portable, battery-operated, chip-based test that can be placed in peripheral laboratories, serving as a point-of-care test. It also detects rifampicin resistance, which is crucial in the management of TB. Our review comprehensively covers the functionality and workflow of the Truenat MTB assay, in addition to its cost-effectiveness and diagnostic accuracy, based on recent evidence. We also discuss the merits and drawbacks of alternative diagnostic tests available for detecting TB and rifampicin resistance. Truenat assays are rapid molecular tests that revolutionized TB diagnosis, moving toward peripheral testing. Evidence indicates that the Truenat MTB Plus performs better than the original Truenat MTB, with an approximate LOD of 30 CFU/ml. The 2025 WHO guidelines rely exclusively on data from Truenat MTB Plus. We need larger studies on the newer Truenat MTB Ultima to evaluate its performance on tongue swabs. Additionally, data on the accuracy of Truenat MTB in children remains scarce, emphasizing the importance of further research in this group. Evidence regarding its accuracy in detecting rifampicin resistance is also limited, requiring larger studies and technological advancements. Truenat MTB will remain crucial in the fight to eliminate TB in the future. Early diagnosis of tuberculosis (TB) is essential to stop its spread, prevent drug resistance, and reduce deaths and disabilities due to TB. Truenat assays are molecular tests that can detect the bacterial DNA and resistance to rifampicin – a key first-line TB drug within few hours. Truenat devices are portable and battery-operated. They use chip-based PCR technology to amplify the bacterial DNA into million folds and target specific genes like nrdB (MTB assay), nrdz, and IS6110 (MTB Plus assay), IS1081 (Truenat MTB Ultima assay) to detect TB and rpoB (MTB-RIF Dx reflex assay) to detect rifampicin resistance. Unlike other molecular tests like Xpert, Truenat can operate in environments up to 40°C and 80% humidity. This makes it ideal for use in rural or resource-limited settings, eliminating the need for transport of samples to air-conditioned labs. Among 100 adults tested with Truenat MTB, it accurately rules out 87 people without TB and detects 86 people with TB. Truenat MTB Plus performs better than Truenat MTB. More research is needed on its use in children and for detecting drug resistance. The World Health Organization (WHO) recommends Truenat as an initial test for TB, expanding its utility to improve TB diagnosis worldwide.