An HCV elimination program aims to diagnose more than 90% of Chronic HCV cases. We critically evaluated the performance of a point-of-care test (POCT) using an HCV Rapid Antibody Test. PWID from 4 Halfway Houses (HWH) in Singapore were recruited from March 2022 to April 2023. Participants were concurrently screened for HCV via venous blood for anti-HCV serology and using fingerstick capillary whole blood (FSWB) and oral mucosal transudates (OMT) for POCT, which were interpreted by trained personnel. A blinded study team member independently assessed images of POCTs. Of 207 participants, 37.3% were anti-HCV positive. Compared to anti-HCV serology, POCT performance on FSWB and OMT were: Sensitivity 81.8 (73.2-90.4), 74.0 (64.2-83.8), p = 0.014; Specificity 100.0 (100.0-100.0), 98.5 (96.3-100), p = 0.157. Sub-group analysis of strict 30-min pre-test nil-by-mouth instruction in 103 subjects reported Sensitivity 77.5 (64.6-90.4), 77.5 (64.6-90.4) and Specificity 100.0 (100.0-100.0) and 98.4 (95.3-100.0). OMT positivity and false-negative outcomes did not correlate with the sample analytical cutoff index signal distribution of anti-HCV Serology. Inter-class correlation between real-time and imaging readings of POCT for FSWB and OMT at 20 and 40 min were Kappa 0.9666, 0.9674; 0.8803, 0.8940. Proper preparation and patient selection enhance test performance. Differences in oral fluid immunoglobulin secretion, oral pathology, age, and sample collection can affect POCT OMT readings. POCT OMT is promising in serial and self-testing, complementing its convenience in testing.
Read full abstract