Quality control and evaluation of human immunodeficiency virus antibody assays used for screening donated blood in China

During 2004, a total of 124 batches of HIV antibody ELISAs from domestic and overseas manufacturers, comprising approximately 60 million tests, were tested for quality and released for screening blood in China. The inter- and intra-batch variation, specificity, and sensitivity were evaluated using a laboratory panel and clinical samples. The inter-batch variation was less than 15% and only 2 of 12 assays had intra-bateh variation of less than 20% for 4 dilutions of a control specimen. 257 samples confirmed positive for HIV antibody and 4826 negative samples from different regions in China were used to evaluate the sensitivity and specificity of the assays. The results showed that the sensitivity is in the range from 93.7% to 100% for assays sampled directly from the manufacturers, and 91.4%-99.6% for those retrieved from the consumers; the specificity was in the range from 97.88 % to 99.97 %. The testing environment may vary in different regions of China. Therefore, manufaeturers should provide robust assays to satisfy the requirements of these diverse environments, and especially reduce the intra-assay variation and improve the stability of the kits.