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Published on: October 31, 2010
Evaluation of performance of human immunodeficiency virus antigen/antibody combination assays in Taiwan
Chun-Kai Chang1, Cheng-Feng Kao2, Pi-Han Lin1
1Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan.
Background:
The fourth-generation human immunodeficiency virus (HIV) combination assay, which can simultaneously detect the presence of anti-HIV antibody and HIV antigen, has been shown to shorten the window period in HIV diagnosis compared with the third-generation HIV antibody immunoassay. This study was aimed to determine the performance of HIV combination assays in Taiwan, where the HIV-1 seroprevalence is 0.007% and HIV-2 infection has never been reported.
Methods:
Performance of three fourth-generation HIV Ag/Ab combination assays (Dia.Pro, Wantai, and Bio-Rad) and one third-generation HIV Ab immunoassay (AxSYM HIV 1/2 gO) was assessed.
Results:
A total of 152 specimens, including 86 confirmed HIV-seropositive and 66 HIV-seronegative samples, were used in the study. The sensitivity of four assays varied from 98.8% to 100%, and specificity varied from 98.5% to 100%. Performance of the 75 equivocal samples, the HIV status of which was confirmed later, in terms of negative prediction varied from 81.8% to 87.5%. The Bio-Rad and Dia.Pro assays exhibited higher sensitivity for the detection of p24 antigen among the three fourth-generation HIV combination assays.
Conclusion:
The three fourth-generation HIV Ag/Ab combination assays exhibited better sensitivity, specificity, and negative prediction than the third-generation HIV Ab immunoassay.

