ABSTRACT
BACKGROUND: To improve the safety of the blood supply in Korea, nucleic acid amplification testing (NAT) for HCV and HIV-1 as a blood screening test has been used by the Korean Red Cross since February 1st, 2005. Until October 31st 2006, a total of 4,037,618 donor samples had been tested and 436 cases showed reactivity for HCV RNA. Only 10 of these cases showed serologically negative antibody results. METHODS: We investigated the characteristics and the follow-up results of the ten donors who showed HCV RNA reactivity and serologically negative results. RESULTS: All the ten donors were identified to be "window period" blood donors with confirmation of their seroconversion by follow-up testing. The average RNA titer of the donors was 9.21x106 IU/mL. Five donors showed high levels of ALT. One donor showed the reversed pattern on the test results for antibody and RNA. CONCLUSION: By detecting five cases of HCV "window period" infection, NAT has increased the safety of the Korean blood supply. But it is considered that NAT can not be a substitute serological test and an adequate follow-up strategy is required for verification of the accurate seroconversion time.