What are the implications of persistent leukocytosis (leukocytes) in urine?

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Last updated: April 3, 2025View editorial policy

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From the Guidelines

Chronic leukocytes in urine, also known as persistent pyuria, requires medical evaluation to identify and treat the underlying cause, and the most recent evidence suggests that urinalysis and urine culture should be reserved for those with acute onset of UTI-associated symptoms and signs 1.

Causes and Evaluation

Chronic leukocytes in urine can be caused by various factors, including urinary tract infections (UTIs), interstitial cystitis, kidney stones, or prostatitis in men. The evaluation of chronic leukocytes in urine should include urinalysis for determination of leukocyte esterase and nitrite level by use of a dipstick and a microscopic examination for WBCs 1.

  • If pyuria (≥10 WBCs/high-power field or a positive leukocyte esterase or nitrite test is present on dipstick), a urine culture (with antimicrobial susceptibility testing) should be ordered 1.
  • The minimum laboratory evaluation for suspected UTI should include urinalysis and microscopic examination for WBCs 1.

Treatment

For bacterial UTIs, treatment typically involves antibiotics such as nitrofurantoin (100mg twice daily for 5-7 days) or trimethoprim-sulfamethoxazole (160/800mg twice daily for 3 days) depending on the specific bacteria and local resistance patterns 1.

  • Non-infectious causes may require different treatments, such as anti-inflammatory medications for interstitial cystitis or alpha-blockers for prostatitis.
  • Increasing fluid intake to 2-3 liters daily can help flush the urinary system.

Important Considerations

  • Persistent leukocytes without bacteria might indicate inflammation rather than infection, requiring further investigation 1.
  • Left untreated, chronic inflammation in the urinary tract can lead to kidney damage or other complications, so addressing the underlying cause is essential for long-term urinary health.
  • The use of fluoroquinolones for UTI is not recommended due to the risk of disabling and serious adverse effects, and beta-lactam antibiotics are also not considered first-line therapy due to collateral damage effects and their propensity to promote more rapid recurrence of UTI 1.

From the Research

Chronic Leukocytes in Urine

  • Chronic leukocytes in urine can be an indicator of a urinary tract infection (UTI) 2
  • The presence of leukocytes in urine can be detected using standardized microscopic and flow cytometry methods, with a leukocyte cutoff value of 87.2/μL having a sensitivity and specificity of 98.33% and 95%, respectively 2
  • Urine culture and susceptibility testing are essential for diagnosing UTIs and guiding antibiotic selection, especially in patients with recurrent infections or treatment failure 3, 4
  • The diagnosis of UTIs can be confirmed by the microbiology culture of urine, which requires at least 48-hour turnaround time, or by using automated urine flow cytometry for rapid diagnosis 2

Treatment of UTIs

  • First-line antibiotics for uncomplicated UTIs include nitrofurantoin, fosfomycin, trimethoprim, and trimethoprim/sulfamethoxazole 3, 4
  • The choice of antibiotic should be guided by urine culture and susceptibility results, as well as local susceptibility patterns 3
  • Treatment options for UTIs caused by multidrug-resistant organisms, such as extended-spectrum β-lactamase-producing Enterobacteriaceae, include nitrofurantoin, fosfomycin, pivmecillinam, fluoroquinolones, and carbapenems 3

Laboratory Diagnosis of UTIs

  • Urine dipstick analysis and urine culture and sensitivity analyses are commonly used diagnostic tests for UTIs 5
  • Automated urine flow cytometry can improve the rapid diagnosis of UTIs by analyzing urine sediment 2
  • The use of certain cutoffs for bacterial and leukocyte parameters in urine flow cytometry can demonstrate good performance in detecting acquired symptomatic UTIs 2

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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