Anti-hepatitis C virus serology in patients affected with congenital coagulation defects: a comparative study using three second generation ELISA tests.

We determined the prevalence of anti-hepatitis C virus (HCV) antibodies in 34 patients affected with congenital coagulation disorders attending the Haemophilia Centre of Padua, Italy. Serological tests were carried out by three second generation enzyme linked immunosorbent assays (ELISA), two based on recombinant proteins (Ortho and Abbott) and one based on synthetic peptides (Behring) as antigenic substrate. The repeatedly reactive specimens were further assayed by the supplemental 4-antigen recombinant immunoblot assay (RIBA) (Chiron and Ortho). Moreover, we performed the dot-blot Matrix test (Abbott) on the samples showing discrepant results by the three ELISA tests. Twenty-six patients (76.5%) were anti-HCV positive using all three ELISA tests; 25 were confirmed by the supplemental RIBA test, the other one was indeterminate. Two samples were in a gray-zone only using the anti-HCV ELISA Abbott. These were positive by the RIBA; in contrast, such samples showed no reactivity with the Matrix test. In accordance with the current literature, these data show an equivalence between the 2nd generation screening tests (ELISA), at least when applied to a high risk population as in the present study. Further, these screening tests demonstrated a reliable specificity, since most of the ELISA-reactive specimens were confirmed by the supplemental RIBA test. In contrast, combined use of the anti-HCV tests could be useful when high sensitivity is requested, as in the case of blood donor pretransfusion screening.