What is the best approach to test for Herpes Simplex Virus 2 (HSV2) in a patient who had unprotected sex with an HSV2 positive patient 2 weeks ago and is currently asymptomatic?

Testing for HSV-2 in an Asymptomatic Patient with Recent Exposure

For an asymptomatic patient with recent exposure to HSV-2 (2 weeks ago), type-specific serologic testing should be performed no earlier than 12 weeks after the exposure to allow sufficient time for antibody development. 1

Immediate Testing Options

For Asymptomatic Patients:

• No immediate testing is recommended at 2 weeks post-exposure if asymptomatic
• Viral shedding detection methods (PCR/NAAT) will likely be negative without lesions
• Antibodies take time to develop and won't be detectable this early

Recommended Testing Algorithm

1. Wait Period Required:

   • Minimum 12-week waiting period after exposure before serologic testing 1
   • Testing too early will likely produce false-negative results

2. Preferred Test After Wait Period:

   • Type-specific glycoprotein G-based serologic testing (EIA or CLIA) 1
   • These tests can differentiate between HSV-1 and HSV-2 antibodies
   • Sensitivity for HSV-2 is approximately 92%

3. Testing Sites:

   • No need for specific anatomical site sampling in asymptomatic patients
   • Blood sample for serologic testing is sufficient

Important Clinical Considerations

Test Limitations:

• HSV-2 serologic tests may lack specificity, particularly with low index values 1
• False positives can occur, especially in low-prevalence populations
• False negatives are possible if tested too early after exposure

Patient Counseling:

• Explain the window period for antibody development
• Discuss that asymptomatic shedding can occur even without visible lesions
• Advise on safer sex practices during the waiting period

When to Test Earlier:

• If symptoms develop (vesicles, ulcers), immediate testing with PCR/NAAT from lesion specimens is recommended 1
• PCR has substantially higher detection rates than viral culture for active lesions 2

Special Considerations

High-Risk Individuals:

• For patients at high risk for STIs and HIV, consider additional STI screening 3
• Patients with multiple partners or substance use may benefit from more comprehensive testing

Prevention During Wait Period:

• Consistent condom use (though not 100% effective for HSV)
• Avoiding sexual contact during partner's outbreaks
• Consider discussing partner's antiviral suppressive therapy

Follow-up Recommendations

• If serologic testing at 12 weeks is negative but exposure risk continues, consider repeat testing in 6 months
• If positive, provide appropriate counseling about transmission risk reduction and treatment options
• Consider HIV testing, as HSV-2 infection increases HIV acquisition risk 4

Remember that the US Preventive Services Task Force recommends against routine screening for HSV in asymptomatic individuals 5, but targeted testing is appropriate in cases of known exposure to an HSV-2 positive partner 1, 6.