Complement component C1q as a novel biomarker in diagnosing Tubercular Pleural Effusion – an Observational Comparative Study.

<bold>INTRODUCTION:</bold> The diagnosis of Tubercular pleural effusion(TPE) is intercepted by the less accurate microbiological tests and biomarkers. This necessitates a valid biomarker that can accurately diagnose TPE. <bold>AIMS & OBJECTIVES:</bold> To determine C1q as an emerging biomarker in diagnosing Tubercular Pleural Effusion and its utility in distinguishing between tubercular and non-tubercular pleural effusions. <bold>METHODS:</bold> In this study, 60 Tubercular and 40 non-tubercular pleural effusions patients were enrolled. C1q complement level in pleural fluid was quantified by the Enzyme linked immunosorbent assay(ELISA), and the diagnostic performance was assessed by receiver operating characteristic(ROC) curve and accuracy was calculated. <bold>RESULTS:</bold> The analysis showed promising results that C1q could accurately diagnose the Tubercular pleural effusion(TPE). Regardless of age, gender; with a cutoff value of 30,352ng/ml the area under curve, sensitivity, specificity, positive predictive value, negative predictive value of C1q for diagnosing Tubercular pleural effusion were 0.980(95% confidence interval), 90.20%, 95.92%, 95.83%, 90.38% respectively. <bold>CONCLUSION:</bold> This study validated C1q complement protein as a promising novel biomarker in diagnosing TPE with high diagnostic accuracy. Hence C1q as a biomarker could revolutionize the early and accurate diagnosis of TPE, facilitating prompt initiation of treatment and reducing the associated morbidity and mortality.