Evaluation of the Cerebrospinal Fluid (CSF)-Truenat Assay: A Novel Chip-Based Test in the Diagnosis and Management of Tubercular Meningitis at a Tertiary Care Hospital

Cureus. 2024 Nov 26;16(11):e74522. doi: 10.7759/cureus.74522. eCollection 2024 Nov.

Abstract

Introduction: Tuberculosis (TB) continues to be a major health concern that has a significant impact on morbidity and mortality worldwide. Tubercular meningitis (TBM) may be fatal due to its severe neurological outcomes if not diagnosed and treated promptly. The newer molecular diagnostic techniques have brought significant advancements in the detection of Mycobacterium tuberculosis (MTB). One such test is the cerebrospinal fluid (CSF)-Truenat assay which offers several advantages over traditional methods and provides results within a few hours. This is crucial for timely intervention and can further improve patient outcomes. We have evaluated its diagnostic accuracy, its utility, and its usefulness in treatment decisions.

Methods: A cross-sectional study was conducted on 150 patients. The CSF samples were analyzed by both cartridge-based nucleic acid amplification test (CBNAAT) and Truenat (Molbio Diagnostics Private Limited, Verna, Goa, India). Brain imaging was also performed. Patients were divided into four groups, i.e., definite, probable, possible, and non-TBM. Truenat-positive cases were considered definite, and their efficacy and clinical utility for diagnosing and managing TBM were compared with CBNAAT.

Results: A comparative analysis between CBNAAT and Truenat showed concordance for positive results. But it also identified some discrepancies, particularly in cases where CBNAAT was positive and Truenat was negative. Overall, Truenat demonstrated strong diagnostic performance with a sensitivity of 83.75%, a specificity of 88.57%, and overall accuracy of 86% as compared to CBNAAT.

Conclusion: The study highlighted the role of Truenat in improving diagnostic accuracy and guiding cost-effective treatment strategies for TBM as compared to CBNAAT. As molecular tests alone cannot detect bacilli in most cases, a combination of clinical, microbiological, and radiological parameters is also obligatory for diagnosing TBM.

Keywords: cbnaat; cerebrospinal fluid; gene xpert; mycobacterium tuberculosis; truenat; tubercular meningitis.