EVALUATION OF AN ANTIGEN-ANTIBODY “COMBINATION” ENZYME LINKED IMMUNOSORBENT ASSAY FOR DIAGNOSIS OF HEPATITIS C VIRUS INFECTIONS

Abstract

BACKGROUND: Development of “combination” assays detecting in parallel, within a single test,Hepatitis C Virus (HCV) antigens and antibodies, not only reduces the window period in HCV-infectionbut also costs. Reduction of costs is important for developing countries where money and personalresources are limited.METHODS: We compared the Monolisa® HCV Antigen-Antibody Ultra (Bio-Rad Laboratories Limited,Marnes La Coquette, France) with the AXSYM HCV version 3.0 (Abbot Diagnostics, Germany)-the latterassay detecting only antibodies to HCV. Seventy three HCV-PCR positive and negative samples weretested.RESULTS: Although the two assays showed comparable results, two samples from a bone marrowtransplant (BMT) patient of viral loads 7.8 x 10 5 and 8.9 x 10 6 IU/mL could not be detected by theMonolisa® HCV Antigen-Antibody Ultra assay. Failure to detect the two samples with viral loadsconsidered above threshold of detection for antigen proteins suggested a lack of sensitivity by this assayto discover viral capsid protein in patient samples. Genotyping of these samples revealed genotype 1b, aHCV-subtype which is widespread and should thus be easily detected.CONCLUSION: We conclude that although this assay depicts high sensitivity and specificity in detectingantibodies to HCV, it seems not to add further benefit in our study population to detect HCV infectionsby enhanced sensitivity due the potential contingency to trace viral capsid antigens.