Demonstration of the diagnostic agreement of capillary and venous blood samples, using hepatitis-C virus SD Bioline© rapid test: A clinic-based study

Background: Simplifying hepatitis C virus (HCV) screening is a key step in achieving the elimination of HCV as a global public health threat by 2030. Objectives: The objective of this study was to demonstrate the agreement of capillary blood and venipuncture specimens when using SD Bioline(C) HCV, a low-cost rapid diagnostic test (RDT), prequalified by WHO in 2016 on venous blood samples. Study design: Recruitment was conducted prospectively among adult patients presenting for HCV testing at the Medecins Sans Frontieres (MSF) clinic of Preah Kossamak Hospital (Phnom Penh, Cambodia) between October and November 2017. Capillary and venous blood samples were collected from consenting patients and tested with SD Bioline(C) HCV. Two independent, blinded readers, and in the case of disagreement, a third reader, interpreted the results of each blood sample. Concordance between results was compared using Cohen's Kappa interrater reliability statistic. Discrepant sample pairs were tested with an enzyme immunoassay, the reference standard, at the Institute Pasteur of Cambodia. Results: Among 421 pairs of samples collected, reader disagreement occurred for 0.7% (n = 3) of the participants. Sixty-four percent of capillary and venous blood sample pairs tested positive for HCV, with a Kappa statistic of 0.985 between the two methods. Three participants with discrepant sample pair results tested positive with EIA. Conclusions: Capillary and venous blood samples were concordant when tested with HCV SD Bioline in a clinical context. This simplified testing approach is essential to the scale-up of HCV screening and useful in resource-limited settings or among populations for whom venipuncture is problematic.