Multicenter evaluation of a new rapid automated human immunodeficiency virus antigen detection assay

Although human immunodeficiency virus (HIV) antigen assays are of limited v alue for monitoring antiretroviral therapy, they play an important role for confirmatory testing of fourth generation HIV screening enzyme immunoassay (EIA) reactive samples. In a multicenter study, a new automated rapid p24 antigen assay, Elecsys(R) HIV Ag (Roche Diagnostics Boehringer Mannheim Gmb H, Penzberg, Germany), was compared to FDA licensed tests (Abbott HIV-1 Ag monoclonal and Coulter HIV-1 p24 antigen assay). In the evaluation 27 seroc onversion panels were included, sera from the acute phase of infection, sin gle and follow-up samples from HIV antibody positive patients, dilution ser ies of HIV antigen positive standards, sera and cell culture supernatants i nfected with different HIV-1 subtypes (A-H, and O) HIV-2 and recombinant HI V-1 (gag/env) isolates. To challenge the specificity of the new assay, 2565 unselected blood donors, sera from pregnant women, dialysis and hospitaliz ed patients and 407 potentially cross-reactive samples were investigated. A cute HIV infection was detected in three to eight seroconversion panels ear lier with Elecsys(R) HIV Ag than with the alternative assays. Higher number s of serum samples from HIV infected patients tested positive by Elecsys(R) HIV Ag than with the comparative assays. All HIV-1 subtypes and HIV-2 isol ates were recognized with Elecsys(R) HIV Ag. Abbott HIV-1 Ag monoclonal and Coulter HIV-1 p24 antigen assay showed a Variable sensitivity for the diff erent HIV-1 subtypes. The specificity of Elecsys(R) HIV Ag and Coulter HIV- 1 p24 antigen assay were 99.8 and 99.93%, respectively. All the eight sera that were false reactive by Elecsys(R) HIV Ag were tested negative with the Elecsys(R) HIV Ag Neutralization Test. In conclusion, Elecsys(R) HIV Ag wa s more sensitive than the alternative assays and showed a high specificity in combination with the neutralization assay. The very short incubation tim e of Is min and the fully automated procedure of Elecsys(R) HIV Ag which pe rmits direct testing from the primary patient blood collection tube, repres ent a major improvement for routine laboratory diagnosis in comparison to t he alternative assays. (C) 1999 Elsevier Science B.V. All rights reserved.