OBJECTIVEThis study was to compare the performance of three HIV antibody confirmatory assay kits in confirming early HIV infection.

METHODSFive HIV antibody-positive plasma specimens were ten-fold serially diluted and then detected by ELISA. The above diluted specimens were detected with the following three HIV antibody confirmatory assay kits to analyze their sensitivity, including Wantai-RIBA (Recombinant immunoblot assay, Beijing Wantai Biological Pharmacy, China), MP-WB (HIV Blot 2.2 WB, MP Biomedicals Asia Pacific Pte. Ltd., Singapore) and INNO-LIA (INNO-LIA(TM) HIV I/II Score, Innogenetics N.V., Belgium), respectively. These kits were further used to detect 48 ELISA-reactive specimens from 11 sets of HIV seroconversion specimens (a total of 48 samples) which were previously detected as HIV antibody-positive by ELISA.

RESULTSWhen 5 samples were diluted to 100 fold, Wantai-RIBA still can detect them positive. Among the 48 HIV antibody-positive specimens detected with ELISA, the confirmation positive rate for Wantai-RIBA, MP-WB and INNO-LIA were 97.92% (47/48), 81.25% (39/48) and 91.67% (44/48), respectively. There was statistically significant difference between the confirmatory results of Wantai-RIBA and MP-WB (χ(2) = 6.13, P < 0.05), as well as between those of INNO-LIA and MP-WB (χ(2) = 5.48, P < 0.05); however, there was no statistically significant difference between those of Wantai-RIBA and INNO-LIA (χ(2) = 1.33, P > 0.05). For other six HIV seroconversion panels containing indeterminate specimens, the average seroconversion period of time for Wantai-RIBA, MP-WB and INNO-LIA were 0.7, 13.3 and 3.7 days, respectively.

CONCLUSIONCompared with MP-WB, Wantai-RIBA and INNO-LIA could reduce the window period to confirm early HIV infection.