Can a urinalysis be negative for epididymitis?

Can Urinalysis Be Negative in Epididymitis?

Yes, urinalysis can absolutely be negative in epididymitis, particularly in younger patients and those with sexually transmitted infections (STIs), where pyuria is frequently absent despite active disease.

Age-Dependent Patterns of Urinalysis Results

Pediatric and Adolescent Patients (<18 years)

• Urinalysis is negative in the vast majority of pediatric epididymitis cases, with 96.1% (73/76) showing no pyuria despite confirmed disease 1
• Nearly all urine tests (urinalysis and culture) are negative in prepubertal boys, with only 1% showing bacteriuria in one large series 2
• The most common etiology in children is idiopathic (96.1%), explaining the absence of urinary findings 1
• Routine antibiotics are not required in pediatric patients with negative urinalysis; antibiotics should only be considered when pyuria is present with or without positive culture 1, 2

Young Adults (14-35 years)

• In sexually active men aged 14-35 years, the most common pathogens are Chlamydia trachomatis and Neisseria gonorrhoeae, which cause urethritis-associated epididymitis 3, 4, 5
• These STI-related cases frequently present without significant pyuria because the infection originates in the urethra rather than the urinary tract 3
• Only 50.1% of men diagnosed with epididymitis in emergency departments are tested for gonorrhea and chlamydia, and among those tested, 13.8% are positive 6
• The diagnostic evaluation should include urethral swab testing (Gram stain showing >5 polymorphonuclear leukocytes per oil immersion field) rather than relying solely on urinalysis 3

Older Adults (>35 years)

• Men older than 35 years more commonly have enteric organism infections (particularly E. coli) related to urinary tract pathology 3, 5
• In this age group, positive urine cultures are more frequent (20.1% growing bacteria at ≥10,000 CFU/ml), and these patients are more likely to have pyuria, elevated urine white blood cells, bacteriuria, positive leukocyte esterase, and nitrites 6
• However, even in older men, urinalysis can still be negative in cases of non-bacterial etiology 1

Critical Diagnostic Pitfalls

Common Testing Errors

• Relying solely on urinalysis misses the majority of STI-related epididymitis cases in younger men, as these infections originate from urethral pathogens rather than urinary tract bacteria 3, 4
• Current tests for C. trachomatis are not sufficiently sensitive to exclude infection even when negative 3
• The absence of irritative urinary symptoms does not rule out urinary tract infection 4

Proper Diagnostic Approach by Age

For men <35 years (sexually active):

• Obtain urethral Gram stain or intraurethral swab for urethritis diagnosis 3
• Perform nucleic acid amplification testing (NAAT) for N. gonorrhoeae and C. trachomatis on intraurethral swab or first-void urine 3
• Examine first-void uncentrifuged urine for leukocytes if urethral Gram stain is negative 3
• Do not withhold treatment based on negative urinalysis alone 3

For men >35 years:

• Urine culture and Gram-stained smear are more likely to be diagnostic 3
• Look for enteric organisms, particularly in patients with recent urinary instrumentation, surgery, or anatomical abnormalities 3, 5

Treatment Implications

When Urinalysis is Negative

• In sexually active men <35 years with negative urinalysis, empiric treatment for STIs is still indicated: ceftriaxone 250 mg IM single dose PLUS doxycycline 100 mg orally twice daily for 10 days 3, 4, 5
• In pediatric patients with negative urinalysis and negative urine culture, supportive therapy alone (rest, scrotal elevation, analgesics) is appropriate without antibiotics 1, 2, 7
• Failure to treat STI-related epididymitis based on negative urinalysis can lead to infertility and chronic scrotal pain 5

When to Reassess

• If no improvement occurs within 3 days of appropriate treatment, reevaluate both diagnosis and therapy 3, 4
• Consider alternative diagnoses including testicular torsion (surgical emergency), tumor, abscess, or testicular cancer 3
• Perform color Doppler ultrasonography if diagnostic uncertainty exists 4, 1