A policy statement by a group of experts on screening blood donations for contamination by human immunodeficiency virus (HIV), the causative agent of acquired immunodeficiency syndrome (AIDS), is presented in this document. This document provides policy recommendations formed by a consensus conference sponsored by the National Institutes of Health and attended by biomedical investigators, blood bank specialists, clinicians, consumers, and representatives of public interest groups. The recommendations concern these areas: (1) tests that are currently being used to screen for AIDS and test performance characteristics; (2) what constitutes a positive test, how a positive HIV-antibody test should be interpreted, and how these tests should be used; (3) how to handle positive test results; (4) the psychosocial ramifications for blood donors of knowledge of a positive test result; (5) the impact testing has had on transfusion medicine; and (6) what research directions should be pursued. The conclusions in this report call for more sensitive tests to identify infectivity, better methods of discouraging possibly infected donors, and better methods of handling psychological problems occurring in those with positive tests. (ABL)