Laboratory Testing for Assault Victims
All assault victims should receive baseline testing for sexually transmitted infections (STIs) using nucleic acid amplification tests (NAATs), a urine pregnancy test for females, and consideration for HIV and hepatitis B risk assessment, with empirical prophylactic treatment recommended rather than relying on follow-up compliance. 1
Essential Laboratory Tests
STI Screening (Baseline)
- Chlamydia and Gonorrhea: NAAT testing is preferred over culture
- Trichomonas: NAAT vaginal specimen for females 1
- Syphilis testing: Should be offered 3
Pregnancy Testing
- Baseline urine pregnancy test for all females of reproductive age (12-45 years) 1
- Critical for determining emergency contraception eligibility and baseline status
HIV Risk Assessment
Obtain baseline HIV testing if any high-risk factors present 1:
- Chronic sexual abuse
- Multiple perpetrators
- Known HIV-positive perpetrator
- High HIV prevalence geographic area
- Perpetrator with genital lesions
Hepatitis B Status
- Assess vaccination history
- Offer hepatitis B vaccine if not previously immunized 1
Critical Clinical Context
The evidence strongly favors empirical prophylactic treatment over test-and-treat strategies because follow-up compliance is notoriously poor—only 30% of victims return for follow-up care 4. Studies show 10% of assault victims already have gonorrhea at initial presentation 5, and approximately 15% will acquire an STI from the assault 6.
Common Pitfall to Avoid
Do not perform speculum examination solely for cervical STI specimens in adolescents or those who haven't had prior pelvic exams—this can be traumatic and lead to future healthcare avoidance 1. Use non-invasive urine or self-collected vaginal swabs instead.
Timing Considerations
- STI prophylaxis: Administer immediately, don't wait for results 1
- Emergency contraception: Must be offered within 120 hours of assault 1
- HIV post-exposure prophylaxis (PEP): Must begin within 72 hours if indicated 1
Follow-up Testing Schedule
Retest at 3 months for all patients who received prophylaxis, or whenever they next present within 12 months if 3-month follow-up isn't feasible 2. However, recognize that aggressive outreach strategies are needed since follow-up rates remain disappointingly low 4.
What NOT to Routinely Order
The evidence does not support routine comprehensive metabolic panels, liver function tests, or coagulation studies unless specific trauma-related injuries are present requiring those assessments 7. Focus laboratory resources on STI screening, pregnancy testing, and risk-based HIV/hepatitis B evaluation.