Targeted Versus Expanded HIV-1 Testing in a Municipal STD Clinic in San Francisco, CA

Background:
The US Centers for Disease Control and Prevention recently recommended expanding HIV testing in medical settings. However, differences in rates of new HIV cases found in Targeted (testing based on risk profile) versus Expanded (all clients offered HIV testing) frameworks have not been well evaluated.

Objective:
To report rates and risk factors of new HIV infections found during Expanded compared with Targeted testing protocols.

Method:
In this cross-sectional study, from February 1st to June 30th, 2007, the San Francisco municipal STD clinic offered Targeted and Expanded HIV testing on alternate days. The yield and characteristics of new HIV infections identified through each testing framework were compared.

Result:
A total of 1,122 Targeted and 894 Expanded HIV tests were administered to patients during the observation period. The proportion of new HIV infections identified was 3.2% and 1.0% (p=0.001) under Targeted and Expanded testing frameworks, respectively. Characteristics of HIV cases found under the two protocols were similar. Under Targeted testing 94% of new HIV cases found were men who have sex with men (MSM) compared to 78% under Expanded Testing (p=0.17). Methamphetamine use in the prior 6 months (32% vs. 33%, p=1.00), having 2 or more sex partners (66% vs. 78%, p=0.70) and white race (47% vs. 22%, p<0.26) were similar between HIV cases identified under Targeted and Expanded frameworks, respectively.

Conclusion:
Targeted testing identified a higher proportion of HIV infected clients compared to Expanded testing. Additionally, those HIV infected persons identified under the Expanded protocol were similar to those identified under Targeted testing and would have been selected for Target testing under our current clinical protocols.

Implications:
The provision of Expanded HIV testing in some high prevalence settings may not increase the yield of new HIV positives identified.