Abstract
BACKGROUND: Truenat™ is a WHO-recommended rapid molecular test for diagnosing TB and detecting rifampicin resistance, whose performance has been evaluated in a few high TB burden countries. METHODS: A prospective multicentre study was conducted in Brazil to estimate the sensitivity and specificity of Truenat MTB Plus compared to Xpert(®) MTB/RIF Ultra for detecting pulmonary TB. Liquid culture for Mycobacterium tuberculosis and drug susceptibility testing were used as reference. RESULTS: Among 283 participants, 112 (39.6%) had culture-positive pulmonary TB. The sensitivity and specificity of Truenat MTB Plus were respectively 72.7% (95% CI 63.41-80.78) and 99.4% (95% CI 96.71-99.98), compared to 78.4% (95% CI 69.56-85.63) and 99.4% (95% CI 96.67-99.98) for Xpert MTB/RIF Ultra. In 89 people living with HIV (PLHIV), Truenat MTB Plus showed a sensitivity of 45.0% (95% CI 23.06-68.47) and specificity of 100.0% (95% CI 95.64-100.00). Among 71 patients previously treated for TB, Truenat MTB Plus showed sensitivity and specificity of respectively 79.3% (95% CI 60.28-92.01) and 97.5% (95% CI 86.84-99.94). Xpert MTB/RIF Ultra detected rifampicin resistance in 11/88 samples (12.5%) vs 9/72 (12.5%) with Truenat MTB Plus. CONCLUSION: The Truenat MTB Plus performance was comparable to Xpert MTB/RIF Ultra. Both tests demonstrated lower sensitivity in PLHIV.