[Seroprevalence of anti-hepatitis C virus antibodies among blood donors, Brazil].

OBJECTIVE To determine the seroprevalence of anti-hepatitis C virus antibodies (anti-HCV) in blood donors, and to describe the correlation between screening serological test results and confirmatory test. METHODS Epidemiological and laboratorial records of 10,090 blood donors of the blood unit in the city of Apucarana, Brazil, from January 1997 to December 1999 were assessed. Anti-HCV serum antibodies were detected using enzyme-linked immunosorbent assay (ELISA). Serum reactive samples were tested using RIBA (recombinant immunoblot assay). Statistical analysis was performed using Chi-square test, Fischer's test and Kappa index of agreement. RESULTS The results showed that of all the donors, 2,461 (24.4%) were females, 7,629 (75.6%) were males, with ages ranging from 18 to 65 years old. Of 10,090 serum samples tested using ELISA, 88 were reactive to anti-HCV, a seroprevalence of 0.9% that showed no association with either age groups (p=0.197) or sex (p=0.323). When the samples were tested using RIBA, 11 (12.5%) were positive, 14 (15.9%) were indeterminate, and 38 (43.2%) were negative. Statistical analysis revealed a high correlation (kappa index 0.939) between ELISA and RIBA test results. Poorly reactive samples in ELISA showed a high correlation with negative results in RIBA, and samples highly reactive in ELISA showed a high correlation with positive results in RIBA. CONCLUSIONS The results stress the need of confirmatory tests for all anti-HCV reactive samples in screening tests. HVC infection confirmation is paramount for clinical, laboratorial, and histological evaluation of blood donors.