Sally Liska, DrPH
Director, San Francisco Public Health Laboratory
Background: The impact of sexually transmitted diseases is especially severe in HIV infected individuals. Therefore, to determine if detection of HIV infection could be increased by incorporating RNA testing, we pooled samples from clients seeking HIV counseling and testing services at the San Francisco STD Clinic (City Clinic) and tested for HIV RNA in a pilot program. For similar reasons, Los Angeles County Health Department was interested in determining if the detection rate of HIV infection among high risk clients could be increased by testing for RNA. Stored samples collected from STD clinics were pooled and tested for HIV RNA.
Methods: Starting in November, 2003, all clients seeking HIV screening at the San Francisco City Clinic were offered the option of additional testing for HIV RNA. After counseling and giving consent, plasma samples were screened for HIV antibody. EIA negative specimens were pooled and tested for HIV RNA using Bayer’s Versant™ bDNA. Samples from a pool testing positive were tested individually. Results of both antibody and RNA tests were given to the client and follow-up specimens were collected. In the Los Angeles study, stored serum samples collected from at STD clinics for HIV screening were unlinked, pooled and tested for HIV RNA using Roche PCR. Specimens from any positive pools were tested individually.
Results: In the San Francisco pilot, 4,126 samples collected through December, 2004 were screened for both HIV antibody and RNA; 164 (3.97%) were antibody positive and 17 (0.41%) were antibody negative/RNA positive. Los Angeles Health Department tested 33 pools, comprised of 2939 HIV antibody negative specimens collected during a four month period, and detected two (0.068%) PCR positive specimens.
Conclusions: Testing for HIV RNA can be done using pooled samples of serum or plasma and does increase the detection of HIV infection in high-risk populations compared to standard HIV screening methods.
Presenter: Sally Liska, DrPH Email:
Institution: San Francisco Public Health Laboratory
Last Update: April 8, 2005