Identifying hearing impairment in infants and young children.

An important problem in serological screening is the tendency for false positive results to arise owing to "sticky serum" or "ccross reactivity." This problem with specificity can now be overcome by using such tests as the western blot or the polymerase chain reaction. In the study of Brennan and colleagues 2-5% of the 96720 blood donors initially were positive for HTLV-I; only 35 of those were positive on one of two enzyme linked immunosorbent assays (but not true positives) and only five were truly infected with HTLV-I.' Of these five, four were white women with sexual contact as a risk factor, and one a drug misuser.