How to Check for STDs in Women and Men
Screen all sexually active individuals using nucleic acid amplification tests (NAATs) for chlamydia and gonorrhea, serologic testing for syphilis (both treponemal and nontreponemal), and fourth-generation HIV testing, with specimen collection tailored to anatomic sites of sexual exposure. 1
Core Testing Panel for All Sexually Active Individuals
Every sexually active person requires the following baseline tests:
- Chlamydia and gonorrhea NAAT – This is the gold standard with 86-100% sensitivity and 97-100% specificity, far superior to culture methods. 2, 3
- Syphilis serology – Both a treponemal test (EIA or chemiluminescence) AND a nontreponemal test (RPR or VDRL) must be performed together; a single test is insufficient for diagnosis. 2, 1
- Fourth-generation HIV test – This combines antibody and p24 antigen detection, allowing identification 2-4 weeks post-exposure versus 3-6 weeks for antibody-only tests. 1
Specimen Collection: Women
For women, the preferred specimen is a self-collected vaginal swab NAAT, which provides superior sensitivity compared to cervical specimens and can be collected at home. 2, 1
- Vaginal swab NAAT – Optimal for chlamydia, gonorrhea, and trichomoniasis testing; can be self-collected in clinic or at home. 2, 1
- Urine specimen – Acceptable alternative but has slightly reduced performance compared to vaginal swabs. 2
- Cervical specimen – Acceptable for women under 25 years during pelvic examination, but vaginal swabs are now preferred. 2
Additional testing for women:
- Trichomoniasis NAAT – Recommended for all sexually active women, especially those under 25 or with multiple partners; wet mount microscopy misses 30-40% of infections and should not be used. 2, 1
Specimen Collection: Men
For heterosexual men, first-void urine NAAT is the standard specimen for urethral chlamydia and gonorrhea. 2, 4
For men who have sex with men (MSM), testing must include all three anatomic sites based on sexual practices:
- Urine or urethral swab NAAT – For insertive anal or vaginal intercourse (urethral infection). 2, 4
- Rectal swab NAAT – Mandatory for receptive anal intercourse; rectal infections are frequently asymptomatic and missed with urogenital-only testing. 2, 1, 4
- Pharyngeal swab NAAT or culture – Required for receptive oral sex; test for gonorrhea only (pharyngeal chlamydia testing is not recommended due to limited clinical utility). 2, 4
A common critical error is testing only urine in MSM, which misses the majority of rectal and pharyngeal infections. 1, 4
Screening Frequency: Risk-Based Algorithm
Standard-Risk Individuals
Annual screening minimum for all sexually active women under 25 years and men with new or multiple partners. 1, 4
High-Risk Individuals Requiring Every 3-6 Months Screening
Screen every 3-6 months indefinitely if ANY of the following risk factors are present:
- Multiple or anonymous sexual partners 1, 4
- New sexual partners 1
- Substance use during sex (especially methamphetamine) 1, 4
- Previous STI diagnosis within the past year 1
- Inconsistent condom use outside mutually monogamous relationships 1
- Exchange of sex for money or drugs 1
- Partner with known STI or high-risk behaviors 1
- Men who have sex with men (MSM) 1, 4
- HIV-positive status 1, 5
- Incarceration or residence in high-prevalence communities 1
The single annual screen is inadequate for individuals with ongoing high-risk behaviors; a 3-6 month interval is required to detect incident infections promptly. 4
Special Population: Pregnant Women
All pregnant women require universal screening at the first prenatal visit for:
- HIV (fourth-generation test) 1
- Syphilis (treponemal and nontreponemal) 1
- Hepatitis B surface antigen 1
Additional screening for pregnant women under 25 or at increased risk:
- Chlamydia and gonorrhea NAAT (vaginal swab preferred) 1
- Repeat syphilis testing in third trimester and at delivery for high-risk women 1
No infant should be discharged without determination of the mother's syphilis status at least once during pregnancy. 1
Post-Treatment Mandatory Retesting
All patients treated for chlamydia or gonorrhea must be retested at 3 months, regardless of whether partners were treated, because reinfection rates range from 25-40%. 1, 4, 6
- This is not a test-of-cure; it is reinfection screening. 1
- If 3-month retesting is not possible, retest whenever the patient next presents for care within 12 months. 2
Additional Testing Considerations
Hepatitis Screening
- Hepatitis B serologic testing – Recommended for all unvaccinated individuals evaluated for STDs. 1, 4
- Hepatitis C antibody with reflex to RNA PCR – Recommended for MSM, people who inject drugs, and those with multiple partners. 1
Genital Lesions
When genital or oral lesions are present, obtain three mandatory tests regardless of lesion appearance:
- Syphilis serology (treponemal and nontreponemal) 1
- HSV NAAT from the lesion (preferred over culture for higher sensitivity and type-specific results) 1
- Fourth-generation HIV test (lesions increase HIV transmission risk) 1
Do NOT order HSV serology for asymptomatic patients without active lesions; no evidence shows benefit from treating asymptomatic HSV, and false-positives are common. 1
Common Pitfalls to Avoid
- Relying on symptoms alone – 25-40% of STDs are asymptomatic; clinical symptoms are unreliable. 1
- Omitting extragenital testing in MSM – Rectal and pharyngeal infections are frequently asymptomatic and missed with urogenital-only testing. 1, 7
- Using wet mount for trichomoniasis – Misses 30-40% of infections; NAAT should be used instead. 2, 1
- Single syphilis test – Both treponemal AND nontreponemal tests are required for accurate diagnosis. 2, 4
- Forgetting 3-month retest after positive chlamydia/gonorrhea – This is mandatory due to high reinfection rates. 1, 4
- Testing only urine in MSM – Must test all anatomic sites of exposure (urogenital, rectal, pharyngeal). 1, 4
Reporting Requirements
Syphilis, gonorrhea, chlamydia, and HIV are reportable in all U.S. states; clinicians must notify local health departments. 1