Evaluation of the Performance Characteristics of 6 Rapid HIV Antibody Tests

Background. Since 2002, the US Food and Drug Administration has approved 6 rapid human immuno-deficiency virus (HIV) tests for use in the United States. To date, there has been no direct comparison of theperformance of all 6 tests.Methods. Persons known to be HIV-infected and persons who sought HIV testing at 2 clinical sites in LosAngeles, California, were recruited for evaluation of 6 rapid HIV tests with whole blood, oral fluid, serum, andplasmaspecimens.Sensitivityandspecificityoftherapidtestswerecomparedwithvirallysateandimmunoglobulin(Ig) M–sensitive peptide HIV enzyme immunoassays (EIAs).Results. A total of 6282 specimens were tested. Sensitivity was .95% and specificity was .99% for all rapidtests.ComparedwiththeIgM-sensitiveEIA,rapidtestsgavefalse-negativeresultswithanadditional2–5specimens.All rapid tests had statistically equivalent performance characteristics, based on overlapping confidence intervals forsensitivity and specificity, compared with either conventional EIA.Conclusions. All 6 rapid tests have high sensitivity and specificity, compared with that of conventional EIAs. Becauseperformance was similar for all tests and specimen types, other characteristics, such as convenience, time to result,shelflife,andcostwilllikelybedeterminingfactorsforselectionofarapidHIVscreeningtestforaspecificapplication.In 1998, when the Centers for Disease Control andPrevention (CDC) encouraged the use of rapid humanimmunodeficiency virus (HIV) tests to increase the re-ceipt of results among persons tested for HIV [1], onlytheSingleUseDiagnosticSystemforHIV-1(SUDS)wascommercially available in the United States [2]. Since2002, the US Food and Drug Administration (FDA) hasapproved 6 rapid HIV tests [3] that have become in-tegral to initiatives designed to promote more wide-spread HIV testing [4–10].Rapid HIV antibody tests provide results in ,30min [3]. FDA-approved rapid HIV tests (Table 1)employ either immunochromatography (lateralflow) or immunoconcentration (flow-through) tech-niques [11] and contain antigens that correspond toenvelope regions of HIV-1 (gp41, gp120, or both).Some tests also have an HIV type 2 (HIV-2) envelope(gp36) antigen. However, recent studies have docu-mented that rapid HIV tests have lower sensitivity,especially during early infection, than that of someconventional assays [12–14]. False-negative test re-sults have also been observed in individuals with ad-vanced disease [15] and in some persons who arereceiving effective antiretroviral therapy (ART) [16,17]. Because test manufacturers do not explicitlyidentify which reference tests were used to calculatesensitivity and specificity (Table 1), this study wasundertakentocomparecontemporaryrapidHIVtestsand conventional enzyme immunoassays (EIAs) whenperformed on specimens fromthesamepersons.METHODSThe two-phase field study was conducted at the Los An-geles Gay and Lesbian Center (LAGLC), an HIV testing