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Document Details :
Title: Evaluation of the use of a combined HCV antigen/antibody assay in routine laboratory practice
Author(s): VERMEERSCH P, VAN RANST M, LAGROU K
Journal: Acta Clinica Belgica
Volume: 65 Issue: 4 Date: 2010
Background: Combined hepatitis C virus (HCV) antigen/antibody (Ag/Ab) assays offer the advantage of a shorter window phase compared to traditional anti-HCV antibody assays. These assays have been extensively evaluated for the screening of healthy blood donors, but not in routine laboratory practice. Methods: We evaluated the performance of the combined HCV Ag/Ab assay Monolisa Ultra and compared it to Monolisa anti-HCV Plus (which only detects anti-HCV antibodies) in 61 HCV RNA-positive patients (genotypes 1 to 5) and in 276 consecutive AxSYM HCV-reactive patients. Discordant sera were tested with immunoblot and PCR. Results: All 61 PCR-positive sera were positive with AxSYM, Monolisa Ultra, and Monolisa Plus. Of the 276 consecutive AxSYM-reactive patients, 177 were confirmed as HCV-positive, 78 were HCV-negative and 21 were HCV-indeterminate. There were 4 false-positive results with Monolisa Ultra compared to 1 false-positive result with Monolisa Plus. The signal/cut-off ratio in immunoblotnegative sera was significantly higher with HCV Ultra compared to HCV Plus (p<0.01). Sensitivity and specificity in AxSYM-reactive sera were 99.4% and 94.9% for Monolisa Ultra and 99.4% and 98.7% for Monolisa Plus. Conclusion: When used as a secondary test, the sensitivity of the combined HCV Ag/Ab assay Monolisa Ultra was excellent, but specificity was reduced in AxSYM-reactive sera compared to Monolisa Plus.