Revising Expectations from Rapid HIV Tests in the Emergency Department

Abstract

Expanded HIV screening efforts in the United States have increased the use of rapid HIV tests in emergency departments. The reported sensitivity and specificity of rapid HIV tests exceed 99%. To assess whether a reactive rapid oral HIV test result correctly identifies adults with HIV infection in the emergency department. Diagnostic test performance assessment within the framework of a randomized, clinical trial. Brigham and Women's Hospital emergency department (Boston, Massachusetts) from 7 February to 1 October 2007. 849 adults with valid rapid oral HIV test results. Rapid HIV testing with the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test (OraSure Technologies, Bethlehem, Pennsylvania). Patients with reactive rapid test results were offered enzyme-linked immunoassay, Western blot, and plasma HIV-1 RNA testing for confirmation. Specificity and positive likelihood ratio. 39 patients had reactive results (4.6% [95% CI, 3.2% to 6.0%]). On confirmation, 5 patients were HIV-infected (prevalence, 0.6% [CI, 0.1% to 1.1%]) and 26 were non-HIV-infected (8 patients declined confirmation). The estimated rapid test specificity was 96.9% (CI, 95.7% to 98.1%). Sensitivity analyses of the true HIV status of unconfirmed cases and test sensitivity resulted in a positive likelihood ratio of 8 to 32. Western blot alone as a confirmation test provided conclusive HIV status in only 50.0% (CI, 30.8% to 69.2%) of patients at first follow-up. The addition of HIV-1 RNA testing to the confirmation protocol improved this rate to 96.2% (CI, 88.8% to 100.0%). Test sensitivity cannot be assessed because nonreactive OraQuick test results were not confirmed. Although patients with a reactive oral OraQuick HIV screening test in the emergency department had an 8- to 32-fold increased odds of HIV infection compared with the pretest odds, the specificity of the test was lower than anticipated.