Evaluation of an individual-donation nucleic acid amplification testing algorithm for detecting hepatitis B virus infection in Chinese blood donors

BACKGROUND: This multicenter study was performed to evaluate the efficiency of a multiplex individual-donation nucleic acid amplification technology (ID-NAT) and discriminatory testing algorithm for detecting hepatitis B virus (HBV) infection in Chinese blood donors. STUDY DESIGN AND METHODS: A total of 1,205,796 hepatitis B surface antigen (HBsAg)nonreactive donations from 10 blood centers were tested by ID-NATusing the Ultrio assay. Multiplex Ultrio-reactive donations were tested in the discriminatory tests as well as in quantitative polymerase chain reaction (qPCR) and in supplemental electrochemiluminescence immunoassays for HBsAg, hepatitis B surface antibody (anti-HBs), hepatitis B e antigen, and antibody to hepatitis B core antigen (anti-HBc). Meanwhile, a control group of 4317 Ultrio-nonreactive donations was tested for anti-HBc and anti-HBs. RESULTS: Of all donations, 2033 (0.17%) were reactive in the multiplex Ultrio assay. Among 1776 further tested samples, 548 (30.9%) were HBV discriminatory assay (dHBV)-reactive, while 1214 (68.4%) were nonreactive. Of 472 Ultrio+ and dHBV+ samples 86.2% were qPCR positive compared to 15.0% in 1046 Ultrio+ and dHBVsamples. The proportion of anti-HBc+ and anti-HBs( potentially infectious) donations was higher in 409 Ultrio+ and dHBV+ than in 1028 Ultrio+ and dHBVsamples (51.3% vs. 31.1%, p < 0.001). The yield rate of Ultrio+, dHBV+, and qPCR+ donations was estimated at 1 in 2500, but at 1 in 1100 when all supplemental tests were taken into account assuming that 44% of detected donations by Ultrio were false reactive. CONCLUSIONS: A quarter of HBsAg-negative Ultrio+ and dHBV-donations in China are likely given by potentially infectious low-viral-load occult carriers. Although this has no implication for blood safety, the testing algorithm needs to be redesigned to more efficiently discriminate between true and false NATreactivity.