Background:  The US Centers for Disease Control and Prevention (CDC) recommend offering HIV testing to persons admitted to emergency departments (ED). Some ED have found a seroprevalence of approximately 1% when rapid testing is offered. The true seropositivity rate is unknown.

Methods:  Over a 2-week period, demographic and clinical data were extracted from the charts of all ED patients the day after care was provided. Any remaining blood from these patients was linked to the extracted data by a 7-digit random number and all identifying information was then destroyed. HIV testing was performed with the OraQuick Advance Rapid HIV-1/2 Antibody Test (OraSure Technologies, Bethlehem, Pennsylvania) on the blood samples. This study was approved by the local and state Institutional Review Boarads (IRB).

Results:  Over the 2-week period, 2427 patients were seen in the ED and 2019 charts were available for review. Of these, 942 patients had blood available for rapid HIV testing:  133 (14%) of samples were reactive; 64 of 515 (12%) were women, 69 of 427 (16%) were men; 9 of 96 (9%) were Caucasian, 95 of 649 (15%) were African American, 15 of 119 (13%) were Latino, and 11 of 26 (24%) were unknown race; 5 of 23 (22%) of pregnant patients in the ED were reactive; 28 patients reported a history of HIV, but only 25 of them tested positive. There was no difference in disposition:  82 of the 610 (13%) admissions were reactive; 48 of 321 (15%) discharges were reactive.

Conclusions:  HIV seroprevalence in our urban ED is high. Other ED (including our own) have found a seropositivity of 0.8 to 1.5% when the rapid test is offered directly to patients. This latter method may underestimate the true prevalence of HIV among ED patients. More resources may need to be dedicated to diagnosing these infections.