How soon after an initial test should a person without symptoms repeat their sexually transmitted infection (STI) test?

STI Retesting Schedule for Asymptomatic Individuals

For asymptomatic individuals after STI testing, repeat screening should occur at 2 weeks for bacterial STIs (gonorrhea, chlamydia) and at 3 months for HIV and syphilis, with ongoing screening every 3-6 months if risk factors persist. 1, 2

Immediate Follow-Up Testing (2 Weeks)

Bacterial STIs require retesting at 2 weeks because infectious agents may not have produced sufficient concentrations to be detected on initial testing. 1, 2, 3

• Gonorrhea and chlamydia testing should be repeated 2 weeks after initial exposure using nucleic acid amplification tests (NAATs) on urine or site-specific specimens (pharynx, rectum, vagina depending on exposure sites). 1, 2, 3
• This 2-week window is critical—testing too early and stopping there is the most common error, as a negative test at 1 week does not rule out infection. 2
• If initial tests were positive and treated, this 2-week retest is not needed; instead, proceed directly to the 3-month reinfection screening. 1

Three-Month Follow-Up Testing

All individuals require repeat testing at 3 months for HIV and syphilis due to window periods, and for reinfection screening if initially positive for bacterial STIs. 1, 2, 4

HIV Testing at 3 Months

• HIV testing at 3 months post-exposure is mandatory using laboratory-based antigen/antibody tests, as the window period means early infection may be missed on initial testing. 1, 2, 4
• The 3-month timepoint captures the vast majority of HIV seroconversions. 4
• An intermediate test at 4-6 weeks is also recommended by some guidelines to detect earlier seroconversion. 2, 4

Syphilis Testing at 3 Months

• Serologic testing for syphilis (both nontreponemal and treponemal tests) should be repeated at 3 months if initial testing was negative. 2, 4
• Some guidelines recommend an intermediate test at 4-6 weeks post-exposure. 1, 4

Reinfection Screening at 3 Months

• If initial gonorrhea or chlamydia tests were positive and treated, mandatory retesting at 3 months is required due to extraordinarily high reinfection rates. 1, 2
• Reinfection occurs rapidly—within 3.6 months for chlamydia and 6 months for gonorrhea in 25% of previously infected individuals. 2
• Women positive for trichomoniasis also require 3-month retesting. 1

Ongoing Screening for High-Risk Individuals

Individuals with ongoing risk factors require screening every 3-6 months indefinitely, regardless of recent exposures. 1, 2

Risk Factors Requiring Frequent Screening

• Multiple or anonymous sexual partners 1, 2
• Substance use during sexual activity 2
• History of previous STIs 2
• Men who have sex with men 1, 5, 6
• Exchange of sex for drugs or money 2

Evidence Supporting Frequent Screening

• High-risk populations show STI positivity rates of 20% for chlamydia and 17% for gonorrhea with 2-3 monthly screening. 2
• Among MSM on HIV PrEP, quarterly screening detected 34.3% of gonorrhea, 40.0% of chlamydia, and 20.4% of syphilis infections that would have been delayed by 3 months with semiannual screening. 5
• Most asymptomatic STIs occur in individuals reporting condomless sex with a mean of 8.1 partners between quarterly visits. 5

Site-Specific Testing Requirements

Testing must be performed at all exposure sites, as failing to test site-specifically misses a substantial proportion of infections. 2

• Vaginal/urethral exposure: Urine or genital specimens for gonorrhea and chlamydia 1, 2
• Receptive anal intercourse: Rectal specimens for gonorrhea and chlamydia 1, 2
• Receptive oral sex: Pharyngeal specimens for gonorrhea (pharyngeal chlamydia testing not generally recommended) 1, 2
• Women: Vaginal NAAT for trichomonas (can be self-collected) 1, 2

Critical Pitfalls to Avoid

• Never rely on a single negative test shortly after exposure—this is the most critical error in STI screening. 2, 3
• Do not assume condom use eliminates risk—some STIs transmit through skin-to-skin contact in areas not covered by condoms, and condom effectiveness varies widely. 2
• Do not skip the 3-month reinfection screening after positive initial tests—reinfection rates are extraordinarily high even when partners are reportedly treated. 1, 2, 7, 8
• Do not test only at symptomatic sites—most STIs in young adults are asymptomatic, and site-specific testing based on exposure is essential. 2, 6

Special Considerations

Hepatitis B and C testing should be included in initial screening if vaccination status is unknown or risk factors are present. 1, 2

• Baseline hepatitis B serologic testing if not previously vaccinated 1, 2
• Hepatitis C antibody testing with reflex to HCV RNA if positive, with annual rescreening for those at ongoing risk 1