[HIV serology in the early stage of an HIV infection]

Sera were available of 23 individuals before anti-HIV screening tests of the first generation became positive (seroconversion). HIV antigen (p24) became detectable before seroconversion in 21 individuals. HIV antigen disappeared before the first appearance of anti-HIV in 3 instances and shortly after seroconversion in another 17 individuals. As early as HIV-Ag, IgM anti-HIV also became detectable as measured by Western Blot, but these antibodies persisted longer. In 12 individuals anti-HIV as measured by a second generation screening test (using antigens produced by gene technology) also became positive before seroconversion. IgM anti-HIV and HIV-Ag are of help in early diagnosis of HIV infection but cannot be used as screening tests. For anti-HIV screening only tests of the second generation should be used.