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

Objective - The aim of the study was to assess screening assays allowing th e simultaneous detection of HIV antigen and antibodies in order to reduce t he HIV seronegative period. Patients and methods - Sixty one samples from selected early HIV-I 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 II and 250 pg/mL of 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 HIVAg, these assays are less sensitive than p24 Ag screening assays dedicated to the det ection of this marker. (C) 2001 Editions scientifiques et medicales Elsevie r SAS.