Diagnostic performances of Exacto® Triplex rapid test for diagnosis of HIV/HCV/HBsAg: a multicenter, cross-sectional, field study in the Central African Republic.

Introduction: the Exacto® Triplex HIV/HCV/HBsAg (Biosynex, Strasbourg, France) consists in lateral flow, immunochromatographic rapid diagnostic test simultaneously detecting human immunodeficiency virus (HIV)-1 and HIV-2 and hepatitis C virus (HCV)- specific antibodies (IgG and IgM) and hepatitis B virus (HBV) surface antigen (HBsAg) in serum, plasma and whole blood. We herein evaluated its diagnostic performances in the Central African Republic (CAR).

Methods: cross-sectional study was conducted on prospectively collected panel of 550 sera from adult inpatients living in Bangui, including 200 HIV-positive, 100 HBsAg-positive, 50 HCV-positive, 200 negatives to three viruses according to reference immuno-enzymatic serological tests including Murex HCV (Diasorin, Saluggia, Italy) for HCV, Murex HBsAg (Diasorin) for HBV, Genscreen ULTRA HIV Ag-Ab HIV-1/2 Version 2 (Bio-Rad, Marnes-la-Coquette, France) and Murex HIV 1.2.0 Ag/Ab Combination (Diasorin), the 2 tests associated in the parallel algorithm for the reference strategy for the diagnosis of HIV in CAR. Serum samples were tested blindly in duplicate. The findings are reported following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.

Results: the Exacto® Triplex showed 99.5% (95% CI; 98.5-100.0), 96.0% [90.6-100.0] and 99.0% [97.1-100.0] sensitivities for HIV, HCV and HBsAg, respectively. The specificity, positive and negative predictive values (PPV and NPV) were 100.0% for all three viruses. The Youden's J index and Cohen's κ coefficient were 0.99 for HIV and HBsAg. For HCV, Youden's J and Cohen's κ coefficient were 0.96 and 0.98, respectively. In the epidemiological context of the CAR, the PPV and NPV for all three viral infections were high (≥99.0% to 100%).

Conclusion: taken together, our STROBE-compliant study demonstrates that the Exacto® Triplex HIV/HCV/HBsAg showed high sensitivity and specificity for HIV and HBsAg (≥99.0%), and relatively high sensitivity (96.0%) and high specificity (100%) for HCV. These analytical performances are within the limits required by the WHO (i.e. sensitivity ≥99.0% and specificity ≥98.0%) for HIV and HBV. The Exacto® Triplex HIV/HCV/HBsAg is user-friendly at low cost, and appears highly desirable for routine use in the CAR, and likely other Central African countries.