Urinalysis Findings in Males with Gonorrhea and/or Chlamydia
In males with gonorrhea and/or chlamydia, urinalysis typically shows ≥10 white blood cells per high-power field and a positive leukocyte esterase test on first-void urine, indicating urethral inflammation. 1
Key Urinalysis Findings
Leukocyte Esterase and WBCs
- Positive leukocyte esterase test on first-void urine specimen is a key indicator 1
- Microscopic examination of first-void urine sediment showing ≥10 WBC per high-power field 1
- These findings document urethritis, which is the hallmark of these infections in males
Diagnostic Performance
- Leukocyte esterase testing has shown sensitivity of 66.7-100% and specificity of 80-91% for detecting gonorrhea or chlamydia in asymptomatic males 2, 3, 4
- The positive predictive value ranges from 42-67.5%, while negative predictive value is higher at 92.8-94% 5, 4
Distinguishing Features
Gonorrhea
- In symptomatic males, Gram stain of urethral discharge showing polymorphonuclear leukocytes with intracellular Gram-negative diplococci is diagnostic for gonorrhea (sensitivity >95%, specificity >99%) 1
- However, Gram stain has lower sensitivity in asymptomatic men and is not recommended for ruling out infection 1
Chlamydia
- No specific urinalysis findings distinguish chlamydial from gonococcal urethritis
- Both infections present with similar urinalysis findings of pyuria and positive leukocyte esterase
Clinical Application
When to Test
- First-void urine (first 10-30 mL of urine) should be collected for optimal results 6
- Nucleic acid amplification tests (NAATs) on urine specimens are preferred for definitive diagnosis with sensitivity >95% and specificity >99% 6
Limitations
- Urinalysis alone cannot definitively diagnose the specific pathogen
- Approximately 10% of males with urethritis may have negative urinalysis findings despite infection 1
- In asymptomatic males, leukocyte esterase testing performs better in younger populations (≤35 years) 4
Important Considerations
- Co-infection with both gonorrhea and chlamydia is common, occurring in up to 40% of cases 7
- Treatment should target both pathogens even when only one is detected 7
- Urinalysis findings may persist for 1-2 weeks after effective treatment
- False positives can occur with other genitourinary conditions (urinary tract infections, prostatitis)
Pitfalls to Avoid
- Do not rely solely on urinalysis for definitive diagnosis; confirmation with NAATs is essential
- Do not rule out infection based on negative urinalysis in asymptomatic males (sensitivity limitations)
- Do not forget to screen for other STIs, including HIV and syphilis, in patients with positive findings
- Do not assume treatment failure if urinalysis remains abnormal shortly after treatment completion
In summary, while urinalysis findings of pyuria and positive leukocyte esterase strongly suggest urethritis from gonorrhea and/or chlamydia in males, definitive diagnosis requires pathogen-specific testing with NAATs, which should be performed on first-void urine specimens.