Background:  In March 2004, the FDA approved the OraQuick Advance HIV 1/2 Rapid Antibody Test for use with oral fluids.  In December 2005, media reports about high rates of false-positive (FP) oral fluid tests in New York City (NYC) and San Francisco (SF) raised questions about the test’s accuracy.

Methods:  CDC investigated OraQuick performance using the following data sources: (1) 4 studies conducted between 2000 and 2005 in diverse populations in which the test was performed on whole blood and oral fluid collected simultaneously and compared with EIA/Western blot results; (2) post-marketing surveillance conducted from August 2004 to June 2005 at 368 testing sites in 14 states and 3 cities (project areas); and (3), from testing of oral fluid specimens conducted September to November 2005 in NYC and SF test sites.

Results:  Of 12,010 HIV-negative persons tested in the 4 studies combined, OraQuick specificity was 99.9% (95% CI: 99.8-100) with whole blood and 99.6% (95% CI: 99.4-99.7) with oral fluid; serum EIA specificity was 99.7% (95% CI: 99.6-99.8).  In post-marketing surveillance, median specificity for the 17 project areas was 99.98% (range 99.7-100) for 134,247 whole blood tests and 99.90 (range 99.4-100) for 25,614 oral fluid tests.  Excess FPs were observed at 3 sites in NYC and 1 site in SF but not at 18 other sites in the same cities using the same test kit lots.

Conclusions:  Specificity of the OraQuick test is slightly lower with oral fluid than with whole blood, but still well above the FDA’s minimum threshold of 98% for rapid HIV tests.  Investigation continues to identify site-specific factors that may lead to more FP oral fluid test results than expected.