What is the recommended lab test through Quest lab to confirm HSV-1 infection?

HSV-1 Confirmation Testing Through Quest Diagnostics

For symptomatic patients with active lesions, order an HSV PCR/NAAT test that differentiates HSV-1 from HSV-2, as this is more sensitive than viral culture and represents the current standard of care. 1

Recommended Test Ordering Approach

For Symptomatic Patients (Active Lesions Present)

Primary recommendation:

• Order: HSV-1/HSV-2 DNA PCR from lesion swab as the first-line test 1, 2
• This FDA-cleared NAAT is 11-71% more sensitive than viral culture, especially when lesions are past the vesicular stage 1, 2
• Results typically available within approximately 2 hours to 2 days depending on the specific assay 1, 2
• The test differentiates HSV-1 from HSV-2 in a single reaction, which is clinically important for prognosis and counseling 1, 3

Alternative if PCR unavailable:

• Viral culture remains acceptable but has lower sensitivity, particularly for healing lesions 1
• Direct fluorescent antibody (DFA) testing can be used but is less sensitive than PCR 1

For Asymptomatic Patients or When Lesions Have Healed

Order: Type-specific HSV-1 IgG serology using glycoprotein G-based assays 1, 4

• This test differentiates HSV-1 from HSV-2 antibodies 1
• Serology should be limited to patients with clinical presentation consistent with HSV but negative direct testing 1
• Wait at least 12 weeks after suspected exposure before testing, as antibodies take time to develop 4

Specimen Collection Details

For optimal diagnostic yield: 1, 2

• Use cotton-wool or Dacron swabs to collect material directly from the lesion base 2
• For vesicular lesions, pierce the vesicle and collect fluid 2
• Place swab in viral transport medium (VTM) or universal transport medium (UTM) 1
• Transport at room temperature; most specimens are maintained at room temperature, ice not required 1
• Deliver to laboratory within 2 days or refrigerate if delayed 1

Critical Pitfalls to Avoid

Do not rely on serology alone for acute diagnosis: 1

• Serology cannot distinguish between new and old infections 1
• Positive IgG only indicates past exposure, not active infection 4
• Negative serology in early infection (first 12 weeks) does not rule out HSV 4

Ensure type-specific testing: 1, 3

• Always request tests that differentiate HSV-1 from HSV-2, as this affects prognosis 1, 3
• HSV-1 genital infections recur less frequently than HSV-2 2
• Type determination is essential for proper patient counseling 1

Quest-Specific Ordering Considerations

When ordering through Quest Diagnostics: 1

• Verify the specific test code with your local Quest laboratory, as specimen sources and test availability are laboratory-specific 1
• Confirm allowable specimen sources and turnaround time with the laboratory 1
• Request FDA-cleared NAAT assays when available 1