When should STI (Sexually Transmitted Infection) testing be done after sexual assault?

STI Testing After Sexual Assault

STI testing should be performed at the initial evaluation, at 2 weeks post-assault, and again at 6 weeks, 3 months, and 6 months after sexual assault to ensure comprehensive detection of potential infections. 1, 2

Initial Evaluation (Baseline Testing)

• Collect specimens from all sites of penetration or attempted penetration:
  • NAAT testing for gonorrhea and chlamydia 1, 2
  • Wet mount and culture for Trichomonas vaginalis 1
  • If vaginal discharge or malodor is present, examine wet mount for bacterial vaginosis and yeast infection 1
  • Baseline serum testing for:
    • HIV
    • Hepatitis B
    • Syphilis 2
  • Pregnancy testing for women of reproductive age 2

Clinical Pearl: Ensure proper documentation of all findings and collection of specimens for forensic purposes when applicable. Thorough documentation supports both medical care and potential legal proceedings. 2

Follow-up Testing Schedule

2-Week Follow-up

• Repeat culture and wet mount tests unless prophylactic treatment was provided 1
• Assess injury healing and ensure counseling has been arranged 2
• Evaluate medication adherence if prophylaxis was prescribed 2
• Pregnancy testing if applicable 2

6-Week, 3-Month, and 6-Month Follow-up

• Repeat serologic tests for:
  • HIV
  • Syphilis
  • Hepatitis B (if indicated) 1, 2

Prophylaxis Considerations

STI prophylaxis should be considered at the initial visit based on risk assessment:

• Standard STI Prophylaxis:

  • Ceftriaxone 250 mg IM single dose
  • Azithromycin 1 g orally single dose
  • Metronidazole 2 g orally single dose (or Tinidazole 2 g) 2

• HIV Post-Exposure Prophylaxis (PEP):

  • Consider within 72 hours of exposure
  • Higher risk with multiple perpetrators, known HIV-positive perpetrator, genital lesions, or anal trauma 2
  • Consult with HIV specialist for appropriate regimen 1

• Hepatitis B:

  • Offer vaccination if not previously vaccinated
  • Add HBIG if perpetrator is known to be HBsAg-positive 2

• HPV Vaccination:

  • Recommend for eligible individuals who haven't completed the series 2

Special Considerations

Male Victims

• Test all potential exposure sites (anal, oral, urethral)
• Provide the same STI prophylaxis as female victims 2

Children and Adolescents

• Testing approaches should be age-appropriate
• Consult with specialists in pediatric sexual assault care
• Consider the window for prophylaxis (especially for HIV PEP and emergency contraception) 2

Common Pitfalls to Avoid

1. Low follow-up rates: Only about 21% of sexual assault victims seek medical care, and compliance with follow-up is often poor 2

2. Missing the window for prophylaxis: HIV PEP must be started within 72 hours to be effective 2

3. Inadequate testing of all exposure sites: Ensure pharyngeal and rectal specimens are collected when indicated 2, 3

4. Overlooking psychological support: PTSD occurs in up to 80% of victims and requires specific treatment 2

5. Failing to document thoroughly: Proper documentation is crucial for both medical care and potential legal proceedings 2

Important Note: The prevalence of STIs following sexual assault is significant, with chlamydia detected in approximately 5.2% of victims at initial presentation 4. This underscores the importance of both testing and prophylaxis.