E. Calero^1, J. Malia¹, R. Sawyer², L. Brown³, D. Birx¹, B. Branson⁴, N.Michael¹.
¹Walter Reed Army Institute of Research and ²Henry M. Jackson Foundation, Rockville, MD, ³Walter Reed Army Medical Center, Wash D.C., ⁴Centers for Disease Control and Prevention, Atlanta, GA

Background: Recent world events underscore the need for rapid HIV screening techniques, because of both acute demands for blood products that exceed the screened supply and exposures to blood of unknown HIV status during rescue efforts. Clinics that support prevention and counseling also frequently lack the testing capacity to quickly provide HIV screening results. Existing HIV serodiagnostic techniques (EIA/Western blot) are too cumbersome to rapidly screen for HIV infection.

Methods: We compared the performance of an algorithm using three newer, unlicensed HIV rapid test devices--Hemastrip (H)(ChemBio Diagnostic Systems), Multispot (M)(BioRad Laboratories), and Oraquick (O)(OraSure Technologies)--with results of conventional EIA/Western blot. These 3 devices were selected based on their previously demonstrated high sensitivity, specificity, and ease of use. We conducted a retrospective, masked study of 439 archived serum specimens (411 HIV-1 negative and 28 HIV-1 positive as determined by EIA/Western blot). All sera were screened in parallel with three combinations of two rapid devices used together (MO, MH, OH). Concordantly nonreactive samples were coded as nonreactive while concordantly reactive or discordant samples were tested with the third device. Final results were based on ”best of three” rapid test results for all three combinations (MO-H, MH-O, OH-M).

Results: All three rapid test combinations yielded 100% sensitivity and specificity compared with EIA/Western blot. 7 samples with initially discordant rapid tests were correctly resolved as reactive by the third rapid test.

Conclusions: The accuracy of combinations of HIV rapid tests used in a parallel algorithm is comparable to that of EIA/Western blot. These rapid devices could be used in civil-military emergencies or in prevention and counseling clinics to provide rapid and accurate HIV diagnosis.

Presented at XIV International AIDS Conference, July 7-12, 2002, Barcelona, Spain