What laboratory tests should be ordered for a comprehensive sexually transmitted disease (STD) check?

Comprehensive STD Screening Laboratory Tests

A comprehensive STD screening should include tests for syphilis, gonorrhea, chlamydia, HIV, and trichomoniasis, with additional tests based on risk factors and exposure sites. 1

Core STD Screening Tests

For All Patients:

• Syphilis screening: Non-treponemal test (RPR or VDRL) followed by treponemal test if reactive 1
• HIV testing: For all sexually active patients aged 13-64 1
• Gonorrhea and Chlamydia testing: Using nucleic acid amplification tests (NAATs) 1
  • Urine specimens for males
  • Vaginal or urine specimens for females
  • Test sites based on reported sexual behaviors (genital, rectal, pharyngeal) 1, 2

For Women:

• Trichomoniasis screening: NAAT on vaginal specimens 1
• Women <25 years: Routine chlamydia screening regardless of symptoms 1

For Men Who Have Sex With Men (MSM):

• Rectal and pharyngeal testing for gonorrhea and chlamydia if reporting receptive anal or oral sex 1, 2

Testing Technology

NAATs are strongly preferred over culture methods due to:

• Higher sensitivity (detecting up to twice as many infections as culture) 2
• Ability to use non-invasive specimens (urine, self-collected vaginal swabs) 3
• Capability to detect asymptomatic infections (81-98% of infections show no symptoms) 4

Testing Frequency

• Initial screening: All patients should be initially screened for syphilis, and all women should be screened for trichomoniasis 1
• Periodic screening: Based on reported behaviors, presence of other STDs, and community prevalence 1
• High-risk individuals: Consider more frequent testing (every 3-6 months) 5

Special Considerations

For Pregnant Women:

• First prenatal visit: Syphilis, HIV, hepatitis B surface antigen, gonorrhea (if at risk), and chlamydia (if <25 years or with new/multiple partners) 5
• Third trimester: Repeat testing for high-risk women or those under 25 5

For Sexual Assault Victims:

• Baseline testing: Using NAATs for gonorrhea, chlamydia, and trichomoniasis 1
• Hepatitis B vaccination: If not previously immunized 1
• HIV prophylaxis assessment: Within 72 hours of assault 1

Common Pitfalls to Avoid

1. Relying on symptoms alone: Most STIs are asymptomatic (81-98% show no symptoms) 4
2. Inadequate site sampling: Test all potential exposure sites (genital, rectal, pharyngeal) based on sexual practices 1, 2
3. Using outdated testing methods: NAATs are significantly more sensitive than culture methods 2
4. Forgetting partner notification: Essential to prevent reinfection and ongoing transmission 5
5. Missing co-infections: Patients with one STI are often co-infected with others (especially gonorrhea and chlamydia) 1

Remember that a negative test does not rule out infection if performed too soon after exposure, and follow-up testing may be necessary based on risk factors and symptoms.