Determination of antibodies against LAV/HTLV III: comparative evaluation of four different commercial test kits

Abstract

Four different, commercially available ELISA tests for the detection of antibodies against LAV/HTLV III were evaluated for specificity and sensitivity. The relative specificity of the kits was determined by investigating a test panel of 76 sera collected from asymptomatic or symptomatic homosexual men. Completely concordant results were obtained for sera from asymptomatic male homosexuals (11% positive for Anti-LAV/HTLV III) or from patients with the AIDS-related complex (91% positive for Anti-LAV/HTLV III). Differences between the ELISA test kits, however, were observed with sera obtained from patients with AIDS. While Anti-LAV/HTLV III was detected by the Abbott, Electro-Nucleonics, and Organon test in all 17 sera from AIDS patients, the Pasteur test failed to detect Anti-LAV/HTLV III in 7 consecutive sera from an individual patient with late-stage AIDS. The relative sensitivity of the ELISA tests was determined by endpoint titration of confirmed Anti-LAV/HTLV III positive sera from donors of different risk groups for AIDS. The titration experiments demonstrated that the Abbott test clearly was the most sensitive of the ELISA tests studied, followed by the Electro-Nucleonics, Pasteur, and Organon test. The results further indicate that most of the differences of specificity and sensitivity observed between the Anti-LAV/HTLV III tests could be abolished by a modified definition of minimum positive absorbance values.