What laboratory tests and treatment are recommended for a homosexual male presenting with concerns about sexually transmitted infections (STIs)?

STI Laboratory Testing and Treatment for Men Who Have Sex with Men

Men who have sex with men (MSM) require comprehensive three-site testing for gonorrhea and chlamydia (urogenital, rectal, and pharyngeal) using nucleic acid amplification tests (NAATs), along with syphilis serology and HIV testing, as extragenital infections are frequently asymptomatic and would be missed by urogenital testing alone. 1

Laboratory Testing Protocol

Required Baseline Testing for All MSM

• Gonorrhea and Chlamydia (three-site NAAT testing): 1

  • Urogenital: First-void urine specimen or urethral swab
  • Rectal: Rectal swab (even if asymptomatic)
  • Pharyngeal: Oropharyngeal swab (even if asymptomatic)

• Syphilis screening: 1

  • Treponemal-specific test first (EIA/chemiluminescence immunoassay)
  • Followed by nontreponemal test (RPR or VDRL) for confirmation
  • This reverse algorithm is now standard in most laboratories

• HIV testing: 1

  • Should be performed at initial visit
  • Repeated based on risk factors

• Hepatitis B serology: 2

  • Assess vaccination status and immunity

• Hepatitis C screening: 1

  • Particularly important in MSM due to sexual transmission risk

Screening Frequency

Sexually active MSM should undergo repeat STI screening every 3-6 months, with more frequent testing (every 3 months) for those with: 1

• Multiple partners
• Anonymous partners
• Recent diagnosis of other STIs
• Methamphetamine or other substance use
• Unprotected sex outside mutually monogamous relationships
• Exchange of sex for drugs or money
• Partners who report these behaviors

Critical Testing Considerations

Why Three-Site Testing is Essential

The majority of gonorrhea and chlamydia infections in MSM occur at extragenital sites and are asymptomatic. 3 In one study of MSM on PrEP, extragenital infections included 10 oropharyngeal and 8 anorectal gonorrhea cases, plus 1 oropharyngeal and 12 anorectal chlamydia cases—all asymptomatic. 3 Testing only urogenital sites would miss 81-98% of infections in this population. 4

Laboratory Method Specifications

• NAATs are preferred over culture for gonorrhea and chlamydia due to superior sensitivity 1, 5
• Urine specimens are acceptable for urogenital testing in males, though urethral swabs remain an option 1
• Vaginal swabs are preferred over cervical swabs for female patients when applicable 1
• Culture is still required for antimicrobial susceptibility testing if treatment fails 1
• Some NAATs for rectal and pharyngeal sites may not be FDA-cleared but can be used if laboratory has validated performance per CLIA requirements 1

Treatment Recommendations

Uncomplicated Urethritis/Cervicitis (Gonorrhea and/or Chlamydia)

For gonorrhea: 1

• Ceftriaxone 250 mg IM single dose
• PLUS treatment for chlamydia (see below)

For chlamydia: 6, 7

• Azithromycin 1 gram orally single dose, OR
• Doxycycline 100 mg orally twice daily for 7 days

Dual therapy is recommended because coinfection rates are high, and routine cotreatment may prevent development of antimicrobial resistance. 1

Important Treatment Caveats

Quinolones (ciprofloxacin, ofloxacin) should NOT be used for gonorrhea treatment in MSM due to high rates of quinolone-resistant N. gonorrhoeae in this population (23.9% resistance rate). 1

If chlamydial NAAT is negative at time of gonorrhea treatment, the patient does not require empiric chlamydia treatment. 1 However, if chlamydial results are unavailable or a less sensitive test was used, treat for both.

Syphilis Treatment Considerations

All patients with urethritis or cervicitis should have syphilis serology performed, as antimicrobials used for short courses may mask incubating syphilis. 1, 6

HIV-positive MSM with positive syphilis serology at high titer (>1:32) or CD4 count <350 cells/mm³ should undergo CSF examination regardless of syphilis stage. 1

Partner Management

Sexual partners should be evaluated and treated if contact occurred within 60 days preceding symptom onset (or 60 days before testing for asymptomatic patients). 1, 8

For symptomatic males, a 30-day exposure period is sufficient to identify likely transmission sources and recent exposures. 1

Patients should abstain from sexual activity until they and their partners complete treatment and are asymptomatic. 1

Follow-Up and Monitoring

Patients should be reevaluated if symptoms persist after 3 days of treatment, requiring reassessment of diagnosis and therapy. 1

Test of cure is not routinely recommended unless symptoms persist, treatment compliance is questionable, or pregnancy is involved. 1

Patients who "fail" therapy or have repeat positive tests are most likely reinfected by untreated partners rather than experiencing true treatment failure. 1 This underscores the critical importance of partner treatment.

Common Pitfalls to Avoid

• Do not rely on symptoms alone to determine testing sites—extragenital infections are typically asymptomatic in MSM 3, 4
• Do not use quinolones for gonorrhea treatment in MSM due to high resistance rates 1
• Do not skip rectal and pharyngeal testing based on reported sexual practices, as patients may underreport receptive anal or oral sex 1
• Do not assume negative urogenital testing rules out STIs in MSM—three-site testing is essential 3
• Do not forget to evaluate and treat partners—reinfection is the most common cause of persistent or recurrent infection 1, 8