HSV-1 Detection in Urinalysis
HSV-1 does not show up on standard urinalysis; however, first-catch urine specimens can be collected and tested specifically for HSV using nucleic acid amplification testing (NAAT/PCR) or viral culture when urethral involvement is suspected. 1
Understanding the Distinction
Standard urinalysis (dipstick, microscopy, routine culture) does not detect HSV-1 or any herpes simplex virus. 1 The confusion often arises because urine can be used as a specimen source for specialized HSV testing, but this requires specific viral diagnostic methods—not routine urinalysis. 1
When Urine Specimens Are Appropriate for HSV Testing
Urine collection is recommended in specific clinical scenarios:
Males with urethral symptoms: When dysuria follows treatment for gonorrhea/nongonococcal urethritis, first-catch urine (first 10-20 mL) should be collected after avoiding urination for at least 2 hours. 1
Urethral involvement suspected: HSV can be isolated from the urethra in 28% of men with first-episode genital herpes infection. 2
Alternative to urethral swabbing: First-catch urine provides a less invasive option compared to inserting swabs into the urethral meatus. 1
Proper Diagnostic Approach for HSV-1
The gold standard for HSV diagnosis requires direct sampling from lesions:
NAAT/PCR with HSV typing provides >90% sensitivity and specificity and is the preferred diagnostic method. 2
Specimen collection technique: Open vesicles with a sterile needle, collect vesicular fluid with a cotton-wool or Dacron swab, then vigorously swab the base of the lesion to obtain epithelial cells. 2
Timing matters: Vesicular lesions yield significantly higher positivity rates than ulcerative or healing lesions. 2
Common Clinical Pitfall
Do not rely on routine urinalysis to detect HSV-1. 1 If HSV infection is suspected (oral lesions, genital lesions, urethral symptoms), you must specifically order HSV NAAT/PCR or viral culture from appropriate specimens—either direct lesion swabs or first-catch urine when urethral involvement is present. 2, 3 Standard urine dipstick, microscopy, and bacterial culture will not identify viral infections. 1
Type-Specific Testing Importance
Always request HSV typing (HSV-1 vs HSV-2 differentiation) as this is critical for counseling—12-month recurrence rates differ dramatically: HSV-2 (90%) versus HSV-1 (55%). 2 HSV-1 increasingly causes genital herpes and can be detected from genital specimens or first-catch urine when appropriate testing methods are used. 3, 4