Comparative analysis of Truenat™ MTB Plus and Xpert^® Ultra in diagnosing tuberculous meningitis

BACKGROUND: Diagnostic delay and drug resistance not only worsen the outcomes of tuberculous meningitis (TBM), but are also important impediments to TB elimination efforts. Given the need for a near point-of-care test suitable for primary healthcare centres and simultaneous detection of resistance, Truenat™ MTB Plus assay was evaluated on a large cohort of TBM patients. METHODS: Truenat assay was performed on 148 cerebrospinal fluid specimens (76 definite TBM, 32 probable TBM and 40 non-TBM controls) and its performance was compared with Xpert ® Ultra. RESULTS: The overall sensitivity of Truenat and Ultra was respectively 78.7% and 67.6% in diagnosing TBM, and respectively 85.5% and 96% in diagnosing definite TBM. Twenty-three additional cases were detected using Truenat and 11 using Ultra. Truenat missed seven cases of rifampicin (RIF) resistance and indicated false RIF resistance in four cases. CONCLUSION: Performance of Truenat was comparable to that of Ultra in diagnosing TBM and inferior to Xpert Ultra in determining RIF resistance.