Evaluation of a system using oral mucosal transudate for HIV-1 antibody screening and confirmatory testing. OraSure HIV Clinical Trials Group.

Objective: To determine accuracy of a human immunodeficiency virus type 1 (HIV-1) antibody testing system using a device to collect and stabilize oral mucosal transudate (OMT), a fluid with increased levels of IgG; an enzyme immunoassay (EIA) screening test optimized for OMT; and a Western blot confirmatory test designed for use with OMT.

Design: The OMT specimens were tested by EIA and, if indicated, confirmatory Western blot according to a standard testing algorithm. The OMT results were compared with true HIV status as determined by serum testing and/or clinical diagnosis.

Patients: Specimens from 3570 subjects (2382 at low risk, 698 at high risk, 242 with acquired immunodeficiency syndrome [AIDS], and 248 "nonspecificity" [persons with diseases associated with an increased frequency of false-positive results in HIV testing]) were collected at 11 geographically diverse sites (including blood banks, public health clinics, general medical clinics, HIV clinics, sexually transmitted disease clinics, and a hemophilia center) in the United States.

Main Outcome Measures: Overall accuracy of testing OMT for HIV-1 antibodies compared with true HIV-1 antibody status; sensitivity and specificity of OMT EIA and Western blot.

Results: Sensitivity of OMT EIA testing in 673 true-positive subjects was 99.9% (672/673). The OMT Western blot results in the 673 true-positive subjects were positive in 665 and indeterminate in 8. The EIA followed by Western blot (if EIA was repeatedly reactive) yielded a negative result in 99.9% (2893/2897) of OMT samples from true negatives and an indeterminate result in 4. The OMT testing system provided the correct result or would trigger appropriate follow-up testing in 3569 (>99.9%) of 3570 cases.

Conclusion: HIV-1 antibody testing of OMT samples is a highly accurate alternative to serum testing.