PREVALENCE OF ANTIBODY TO THE HUMAN-IMMUNODEFICIENCY-VIRUS AMONG CLINICAL LABORATORY SPECIMENS - FINDINGS FROM A SURVEY OF PRIMARY-CARE PHYSICIANS

To evaluate human immunodeficiency virus type 1 (HIV-1) infection amon g patients of primary care physicians, we performed anonymous, unlinke d HIV-1 antibody testing on leftover blood specimens submitted to 10 l arge commercial clinical laboratories for complete blood cell count or hematocrit determination, the most commonly ordered diagnostic tests. From January through August 1990, 55,613 specimens submitted by gener al internists, pediatricians, and family practitioners were sampled; 1 ,104 (2.0%) had HIV-1 antibody. Seroprevalence among the laboratories varied 50-fold, from 0.3 to 12.4%. The HIV-1 prevalence at each labora tory was not always consistent with the AIDS incidence in the area ser ved by the laboratory. Overall the seroprevalence was almost eight tim es higher in men (3.9%) than in women (0.5%). Specimens from seroposit ive persons, especially from men, were unevenly distributed among the physician practices; only three practices submitted approximately 50% of all specimens from seropositive men. These data indicate that a few physicians treat the majority of HIV-1-infected primary care patients . The HIV-1 prevalence among specimens at a clinical laboratory is thu s determined by whether few physicians submit specimens to that labora tory. These results could be of use, for instance, in analyzing propos als to mandate physician reporting of HIV-1 infection. The high HIV-1 prevalence among laboratory specimens underscores the potential for ex posure to HIV-1-infected blood by clinical laboratory personnel and em phasizes the need for universal precautions for all blood specimens.