[Evaluation of a new vesion of the human immunodeficiency virus antigen and antibody combination assay with improved sensitivity in HIV-1 p24 antigen detection].

The performance of a new version of the HIV p24 antigen and antibody combination assays (Genscreen Ultra HIV Ag-Ab) was evaluated by comparing it with three other fourth-generation enzyme immunoassays (Architect HIV Ag/Ab Combo assay, VIDAS HIV DUO Quick and Genscreen Plus HIV Ag-Ab). The assays were examined with 200 HIV positive samples, 1,000 HIV negative samples, 30 samples (28 positives including 24 samples of subtype A, B, B', C, D, F, G, B/D, CRF01_AE in HIV-1 group M, one sample of HIV-1 group O, three samples of HIV-2 and two negatives) of one worldwide HIV performance panel, 59 samples of ten HIV-1 seroconversion panels and the WHO international standard HIV-1 p24 antigen. Both the sensitivity and specificity of Genscreen Ultra HIV Ag-Ab were 100%. All of the 28 positive samples in the worldwide HIV performance panel were positive. The days of the earliest detection in the ten seroconversion panels were the same in three assays (Genscreen Ultra HIV Ag-Ab, Architect HIV Ag/Ab combo assay and VIDAS HIV DUO Quick). Genscreen Plus HIV Ag-Ab which is a former version of the Genscreen Ultra HIV Ag-Ab detected the earliest positive sample one bleed slower than the other three assays in 5 of 10 seroconversion panels. The p24 antigen limit of detection was determined in two ways, using the WHO international standard and three samples from HIV-1 antigen panels; the values obtained were 1IU/mL and 3.5-9.9 pg/mL for Genscreen Ultra HIV Ag-Ab, 1U/mL and 7.1-9.9 pg/mL for Architect HIV Ag/Ab combo assay, 0.5IU/mL and 4.0-7.1 pg/mL for VIDAS HIV DUO Quick, and 32.0-56.5 pg/mL for Genscreen Plus HIV Ag-Ab. In this study, we have shown that Genscreen Ultra HIV Ag-Ab has the sensitivity, specificity and p24 antigen limit of detection that is equal to those of two typical fourth-generation assays. This assay can be considered useful and reliable for HIV screening.