The significance of HIV-1-indeterminate western blot results in blood donor populations.

Until recently it has been difficult to counsel blood donors with human immunodeficiency virus-1 (HIV-1)-indeterminate Western blot results due to a lack of information concerning the significance of this finding. Reports from several investigators have provided laboratory, epidemiologic, and prospective follow-up data that have clarified the potential significance of this laboratory finding. It has been established that the band patterns observed in an HIV-1-indeterminate Western blot result are important in predicting the significance of the result; specifically, the absence of p24 or envelope glycoprotein reactivity has not been associated with HIV-1 infection, whereas the presence of p24 reactivity has infrequently been the first sign of HIV-1 seroconversion. These data provide the basis for formulating policies concerning the notification and counseling of blood donors with HIV-1-indeterminate Western blot patterns.