Effects of heat inactivation on HIV antibody screening and confirmatory test systems

In order to evaluate the effect of heat inactivation on serum undergoing testing for HIV antibody, 100 heat-inactivated and nonheat-inactivated serum samples were tested by two modifications of Abbott's screening assays for human T-cell lymphotropic virus type-III (lot numbers 1037 and 3036) and by two confirmatory assays (Cambridge BioScience CBre3-EIA; Damon Corporation Western blot). The samples consisted of 75 HIV antibody-negative and 25 HIV antibody-positive sera. The specimens were divided into two equal aliquots. One set was not subjected to heat inactivation, while the others were subjected to heat inactivation at 56°C for 30 min. Heat inactivation had no significant effect on the HIV-position sera; however, heat-inactivated, negative sera evaluated by Abbott lot numbers 1037 and 3036 resulted in false-positive rates of 8% and 7%, respectively. No false positives were generated by the two confirmatory assays; however, the CBre3-EIA recombinant envelope protein assay had a significantly increased optical density reading following heat inactivation of the negative sera. The Western blot procedure used in the study was not affected by heat inactivation.