Evaluation of Chlamydia and Gonorrhea Screening Criteria

BACKGROUND AND OBJECTIVES: The advent of more sensitive diagnostic testing technologies and competition in public healthcare spending have resulted in a reevaluation of sexually transmitted disease (STD) screening practices in an attempt to target populations at greatest risk. Screening among populations with a < 2% prevalence of chlamydia and a < 1% prevalence of gonorrhea may not be cost-effective. GOAL: To identify subpopulations with a low prevalence of chlamydia or gonorrhea. STUDY DESIGN: The prevalence of genital chlamydia and gonorrhea among asymptomatic STD patients screened from 1997 to 1998 at San Francisco City Clinic was stratified by demographic and behavioral risk factors. RESULTS: The prevalence of chlamydia and gonorrhea was 3.4% and 1.1% among asymptomatic women and 4.0% and 1.0% among asymptomatic men, respectively. Two low-prevalence subpopulations identified among asymptomatic patients were women older than 29 years (chlamydia, 1.2%) and men who have sex with women (gonorrhea, 0.8%). CONCLUSIONS: These data identified low-prevalence subpopulations among asymptomatic STD patients. As a result, the STD screening criteria at San Francisco City Clinic were changed accordingly.