Evaluation of a new assay for simultaneous detection of HCV core antigen and anti-HCV antibodies

Abstract number: p650

Carlos  S., Fornieles  C., Chueca  N., Alvarez  M., Bernal  C.

Objective: 

The serological HCV diagnosis may present false negative results in the window period, which can be reduced by doing HCV RNA or HCV core Ag. A new ELISA technique for simultaneous detection of HCV core Ag and anti-HCV antibodies has been studied and evaluated for laboratory routine use.

Materials and methods: 

1491 sera with anti-HCV antibodies request received in our laboratory and 3 seroconversion panels with 24 serum samples were analysed. All these samples were tested by a routine assay which detects anti-HCV antibodies (Assay 1, Ortho HCV 3.0 ELISA), and by the new one that detects both HCV core Ag and anti-HCV antibodies simultaneously (Assay 2, Monolisa HCV Ag/Ab Ultra, Bio-Rad). All positive sera were confirmed by recombinant immunoblot (INNO-LIA de Innogenetics).

Results: 

The number of positive (303) and negative (1188) sera was the same for both techniques; however, 6 sera had divergent results. They are shown in the following table: Considering routine technique 1 as reference, the Ag/Ab assay had a sensitivity of 99.01% and a specificity of 99.75%. 99.07% of the negative sera and 93.72% of the positive ones presented an index far from the cut off. Considering the seroconversion panels, in all cases the combination assay reduce the window period.

Conclusions: 

The new assay for simultaneous detection of HCV core Ag and anti-HCV antibodies presents very good sensitivity and specificity values and it can differentiate very well positive and negative results. This makes it a valuable assay for routine diagnosis which allows early detection of HCV infection.