INDETERMINATE WESTERN BLOTS AND PROBABILITY OF HIV INFECTION.

Testing for antibodies to human immunodeficiency virus (HIV) involves screening with an enzyme immunoassay and confirming a positive test with the more specific Western blot method. But some people have repeatedly indeterminate Western blot results, and it is not clear what conclusions to draw about their HIV status.

In this study of 99 volunteer blood donors with repeatedly indeterminate Western blot results, the authors used a variety of other methods to detect HIV infection, including the serum antigen test, blood culture, and the highly sensitive polymerase chain reaction. Antibodies to HTLV-I and HTLV-II, the other known human retroviruses, were also assessed.

None of the 99 subjects had any evidence of HIV infection over a 14-month foll…