Background:
In the 1980's at the onset of the AIDS epidemic, STD prevalence among men who have sex with men (MSM) declined; however, in the past decade, increases in STDs have been seen. Most STD data in MSM are STD clinic-based; limited data exist on STDs in MSM attending primary care clinics.

Objective:
To describe gonorrhea/chlamydia test positivity and syphilis seroreactivity in asymptomatic MSM seen at the largest primary care clinic for MSM in New England and to describe STD test positivity by reason for STD testing.

Method:
As part of CDC's MSM Prevalence Monitoring Project, all medical visits (21,784) for MSM attending Fenway Community Health Center (Boston) were reviewed. STD test positivity (chlamydia, gonorrhea, and syphilis reactivity), was determined by demographic characteristics, symptoms and reason for testing.

Result:
Overall, 22.9% (4977/21784) MSM were tested for an STD. Mean age was 38 years (range: 18-65 years); 82% were White, 5% were Black, and 4% were Hispanic. Sixty-six percent of MSM tested were asymptomatic; 7% of these asymptomatic MSM tested positive for at least one STD. Positivity varied by reason for STD testing: 4.4% (114/2573) for patients routinely screened, 6.9% (19/276) for patients who reported having high risk sex, and 17% (43/253) for patients exposed to an STD. Among all asymptomatic MSM tested, 10% had urethral gonorrhea; 1.7% had pharyngeal gonorrhea; 5.6% had rectal gonorrhea; 2.3% had urethral chlamydia; and 5.9% were seroreactive for syphilis.

Conclusion:
Rectal gonorrhea test positivity and syphilis seroreactivity were high in asymptomatic MSM; STD test positivity was highest in MSM tested due to an STD exposure or reporting high risk sex.

Implications:
Primary care clinics should screen asymptomatic MSM for STDs; screening for rectal gonorrhea should be prioritized given the high prevalence of asymptomatics disease and high risk of HIV transmission.