Rapid HIV screening: missed opportunities for HIV diagnosis and prevention.

BACKGROUND

Although rapid HIV tests increase the number of persons who are aware of their HIV status, they may fail to detect early HIV infection.

OBJECTIVES

To evaluate the sensitivity for early HIV infection of several rapid tests and third- and fourth-generation assays compared with nucleic acid amplification testing (NAAT).

STUDY DESIGN

Sensitivity for early HIV infection was evaluated using 62 NAAT-positive/WB-negative or indeterminate specimens from the CDC Acute HIV Infection study. Specimens underwent third-generation testing with Genetic Systems 1/2+O(®) and rapid testing with Multispot HIV-1/HIV-2. A subset was also tested with four FDA-approved rapid tests and Determine HIV-1 Antigen/Antibody Rapid Test(®) and Architect HIV Antigen/Antibody Combo(®), both fourth-generation tests.

RESULTS

Of 99,111 specimens screened from April 2006 to March 2008, 62 met the definition for early HIV infection (60 NAAT-positive/seronegative and 2 NAAT-positive/Western blot indeterminate). Third-generation testing correctly detected antibody in 34 specimens (55%; 95% confidence interval (CI): 42-67); Multispot detected antibody in 16 (26%; 95% CI: 16-38). Of the 62 specimens, 33 (53%) had sufficient quantity for further testing. Rapid test sensitivities for early HIV infection ranged from 22-33% compared with 55-57% for the third-generation assay and 76-88% for the fourth-generation tests.

CONCLUSIONS

Many rapid HIV tests failed to detect half of the early HIV infection cases in whom antibody was present. Programs that screen high-incidence populations with rapid tests should consider supplemental testing with NAAT or other antigen-based tests. These data support the need for more sensitive antigen-based point-of-care screening tests for early HIV infection.