Can a urinalysis (urine analysis) detect Sexually Transmitted Infections (STIs) in males?

Can Urinalysis Detect STIs in Males?

A standard urinalysis alone cannot detect STIs in males—you need nucleic acid amplification testing (NAAT) performed on urine to diagnose common STIs like chlamydia and gonorrhea. 1

Understanding the Distinction

A critical distinction exists between a routine urinalysis (which looks for white blood cells, bacteria, nitrites, and other general markers) versus STI-specific testing performed on urine specimens:

Standard Urinalysis Limitations

• A routine urinalysis is not an STI test—it only detects inflammatory markers like pyuria (white blood cells in urine) that suggest urethritis but cannot identify the specific pathogen 2
• Pyuria on urinalysis can indicate urethritis from STIs, but also from non-STI causes, making it non-specific 3
• The leukocyte esterase test (LET) on urinalysis has shown variable sensitivity (46-100%) for detecting asymptomatic chlamydial infection and cannot exclude infection 2

NAAT Testing on Urine: The Gold Standard

The CDC recommends urine-based NAAT as the preferred first-line method for diagnosing gonorrhea and chlamydia in males (both symptomatic and asymptomatic) due to its non-invasive nature and superior sensitivity compared to traditional methods. 1

• Modern NAATs on first-void urine specimens achieve 86-100% sensitivity and 97-100% specificity for detecting chlamydia and gonorrhea 4
• Urine NAAT is more sensitive than traditional culture techniques in many settings 2
• For asymptomatic men, urine-based NAATs are strongly preferred over urethral swabs due to higher patient acceptability while maintaining adequate sensitivity 1

Clinical Algorithm for STI Testing in Males

For Symptomatic Males (urethral discharge, dysuria):

• First-line: Order urine NAAT for gonorrhea and chlamydia on first-void urine specimen 1
• Document urethritis by presence of mucopurulent discharge or ≥5 WBCs per oil immersion field on Gram stain of urethral secretions 2
• Both urethral swabs and urine tests are highly effective in symptomatic men, with sensitivities usually exceeding 70% and specificities of 97-99% 1

For Asymptomatic Males:

• First-line: Urine NAAT only—do not use urethral swabs for screening 1, 4
• Traditional non-culture tests on urethral specimens have limited sensitivity and are not recommended for asymptomatic populations 1
• Screen sexually active men who have sex with men (MSM) given median prevalence rates of 16% for gonorrhea and 12% for chlamydia 5

Additional Testing Based on Sexual Practices:

• Assess sexual practices to determine if pharyngeal and rectal testing is necessary, particularly for MSM 1
• Consider syphilis serology and HIV screening for patients with STI history 4

Common Pitfalls and Caveats

False-Positive Results

• False-positive urine NAAT results may occur in older men with non-chlamydial urinary tract infections 1
• Post-treatment testing should be scheduled at least 3 weeks after completing antimicrobial therapy to avoid false results 1

Concurrent STI and UTI

• Having a concurrent STI and bacterial UTI is unlikely—infection with gonorrhea, chlamydia, or trichomonas is not associated with bacteriuria ≥10,000 CFU/mL 3
• This means a positive urine culture for typical UTI bacteria (E. coli, Klebsiella) does not suggest STI presence 6, 3

Asymptomatic Infections

• 70% of chlamydia infections and 53-100% of extragenital gonorrhea/chlamydia are asymptomatic, making symptom-based screening inadequate 4
• Only 50% of men diagnosed with epididymitis/orchitis in emergency departments are tested for gonorrhea and chlamydia, representing a significant missed opportunity 6

Partner Management

• All sexual partners within the preceding 60 days should be referred for evaluation and empiric treatment if gonorrhea or chlamydia is detected 4
• Repeat screening at 3 months is recommended due to high reinfection rates 5, 4