Nationwide nucleic acid amplification testing of hepatitis B virus, hepatitis C virus and human immunodeficiency virus type 1 for blood transfusion and follow-up study of nucleic acid amplification positive donors.

This study described a program for and the results of a nationwide nucleic acid amplification testing (NAT) screening for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus type 1 (HIV-1) by multiplex reagent with a pooled system. After routine serological screening, this test was used in order to be in time for blood transfusions. The Japanese Red Cross currently supplies donated blood all over Japan for blood transfusion. As of January 2000, 2,140,207 units (5,093 pools) were tested by a pool size of 500 and 19 HBV DNA-positive cases and 8 HCV RNA-positive cases were found. Since February 2000, the pool size was switched to 50 and among 420,770 units (8,564 pools), 7 HBV DNA-positive cases and 1 HCV RNA-positive case were found. HIV RNA was not detected in any of the tested pools. Among the 26 HBV DNA positives, 22 were wild type; of these, 6 (23%) had hepatitis B surface antigen (HBsAg) that was undetectable by overnight enzyme immunoassay (EIA). Except for one case, in which coexisting antibody inhibited the immune reaction, all 17 cases that were followed later showed seroconversion. In 10 of these cases, HBV DNA disappeared below the level of detection and seroconversion of IgM anti-HBc and anti-HBc antibody occurred during the observation period. The remaining 4 cases were precore mutants and all had an undetectable level of HBsAg by EIA. Three cases did not show IgM anti-HBc seroconversion, which should be observed during the early stage of HBV infection. As for the HCV RNA, the following types were identified: 2 genotype II (1b), 3 genotype III (2a), and 4 genotype IV (2b). A weak anti-HCV positive reaction was observed in two cases and strong seroconversion in one case among 4 of the cases that were followed. Although it is not 100%, NAT narrows the window period in early-stage infection, resulting in an exponential reduction of the virus load that escapes serological screening tests for blood destined for blood transfusions. In the case of HBV, NAT screening detects HBV DNA in persistently infected individuals with extremely low levels of HBV antigen and antibody often observed in the case of HBV mutants.