Combined tests (p24 Ag and anti-HIV antibodies) during early HIV-1 infection

Objectives - The aim of the study was to assess screening assays allowing t he simultaneous detection of HIV antigen and antibodies in order to reduce the HIV seronegative period. Patients and methods - Sixty one samples from selected early HIV-1 infected patients were assessed. Results - False negative results were observed from two to eight samples wi th the six combined p24 Ag/Ab assays included in this study versus nine to 21 with Ab tests. The mean time delay to detect seroconversion was 0.1 to 0 .8 days for combined tests and one to three days for anti-HIV-1/-2 assays. The limit of HIV Ag detection was sound to be at between 11 and 250 pg/mL o f HIV Ag. Conclusion - The p24 Ag/Ab combined assays allow diagnosing of HIV infectio n earlier than Ab assays. Nevertheless the reduction of the seronegative pe riod is moderate. Except for one which can detect 11 pg/mL of HIV Ag, these assays are less sensitive than p24 Ag screening assays dedicated to the de tection of this marker. (C) 2001 Editions scientifiques et medicales Elsevi er SAS.