AB1561 COMPARISON OF DIAGNOSTIC PERFORMANCE OF TRUENAT™ MTB PLUS AND XPERT® ULTRA (GX) IN PATIENTS OF OSTEOARTICULAR TUBERCULOSIS (OATB): EXPERIENCE FROM NORTH INDIA

<h3>Background</h3> Diagnostic delay and drug resistance not only worsen the outcomes of tuberculosis, but are also important impediments to TB elimination efforts. Prompt and accurate diagnosis of osteoarticular tuberculosis (OATB) along with simultaneous detection of drug resistance is crucial to decrease the morbidity and associated sequelae. <h3>Objectives</h3> Given the need for a near point-of-care test suitable for primary healthcare centers and simultaneous detection of resistance, Truenat MTB Plus (TruPlus), a chip-based real-time polymerase chain reactionassay, was evaluated for the first time for diagnosis of OATB and detection of rifampicin resistance from pus and synovial fluid samples. <h3>Methods</h3> Total of 100 synovial fluid/pus samples (20 microbiologically confirmed OATB[culture-positive], 50 clinically confirmed OATB [culture-negative], and 30 control patients) were subjected to TruPlus assay and Xpert Ultra (GX Ultra)assay; and their performance was compared. Results were evaluated against both culture and composite reference standard. <h3>Results</h3> The overall sensitivity and specificity of TruPlus in diagnosing OATB was 77.14%(54/70) and 100%, respectively. The sensitivity was 90% (18/20) for microbiologically confirmed cases and 72% (36/50) for clinically confirmed cases. Performance of TruPlus was superior to Xpert ultra (sensitivity = 70%). Overall, sensitivity and specificity of GX ultra was 70% and 100%. However, sensitivity of GX Ultra was 85% in culture confirmed cases and 64% (32/50) in clinically suspected cases of OATB. Both TruPlus and Gx Ultra correctly reported Rifampicin resistance in four cases, when compared with phenotypic DST and rpoB gene sequencing. <h3>Conclusion</h3> TruPlus, with its greater portability and higher sensitivity than Xpert, could serve as an important tool for diagnosing OATB and rifampicin resistance at outreach endemic areas. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.