In a prospective study we tested the appearance of IgG and IgM positive viral protein bands in Western blots from six people who seroconverted for anti-HIV antibody. Quantification of the immunoblotted bands was performed by reading the Western blot stripes in Camag scanner and analysed on a 350 computer (digital equipment). In the first serum, all people were negative for anti-HIV antibodies. In the second serum, after 16 to 122 days, all people showed IgM HIV-antibodies to p24. IgG HIV-antibodies were detectable in all people after 18 to 114 days after the second collection. Our data clearly demonstrated that for early analysis of HIV infection only the detection of IgM antibodies to viral protein bands of the Western blot technique provides reliable results and that scanning and advanced integration analysis of the Western blot peaks offer the advantage of direct quantitative comparison of the results, not just qualitative description. Further, this direct quantitative comparison of antibodies to HIV virus protein bands can be used as a prognostic marker for disease states.