How to manage a patient with leukocytes in the urine?

Management of Leukocytes in Urine

For patients with leukocytes in urine, management should be guided by the presence of symptoms, with treatment only indicated for symptomatic patients who have evidence of pyuria and bacteriuria. 1, 2

Diagnostic Approach

• The presence of leukocytes alone is insufficient to diagnose a urinary tract infection (UTI) and requires clinical correlation with symptoms such as dysuria, frequency, urgency, fever, or gross hematuria 1
• Leukocyte esterase testing has moderate sensitivity (83%, range 67-94%) but limited specificity (78%, range 64-92%) for detecting UTIs 1
• When leukocytes are accompanied by a positive nitrite test, the specificity for UTI increases to 96% with a combined sensitivity of 93% 1
• The absence of pyuria (negative leukocyte esterase and no microscopic WBCs) has excellent negative predictive value for ruling out UTI 1

Management Algorithm

For Symptomatic Patients:

1. Confirm presence of UTI symptoms (dysuria, frequency, urgency, fever, gross hematuria, or new/worsening urinary incontinence) 1, 2
2. Perform urinalysis including leukocyte esterase, nitrite, and microscopic examination for WBCs 1
3. Obtain urine culture before starting antibiotics if pyuria (≥10 WBCs/high-power field or positive leukocyte esterase) is present AND symptoms suggest UTI 1, 3
4. Choose antibiotics effective against common uropathogens based on local sensitivity patterns for symptomatic patients with confirmed UTI 2
5. Monitor response to therapy - successful treatment typically shows the deepest decrease in leukocyte counts during the first 24 hours 4

For Asymptomatic Patients:

• Do not perform urinalysis and urine cultures for asymptomatic individuals 5, 1, 6
• No antibiotic treatment is indicated for asymptomatic patients with only leukocytes in urine 6
• No follow-up urinalysis is necessary in asymptomatic patients with isolated leukocytes 6

Special Population Considerations

• Long-term care facility residents: Evaluation is indicated only with acute onset of UTI-associated symptoms (fever, dysuria, gross hematuria, new/worsening urinary incontinence) 5, 1
• Non-specific symptoms like confusion or functional decline alone should not trigger UTI treatment without specific urinary symptoms in older adults 1, 6
• Catheterized patients: Obtain urine by aspiration of the catheter port and not from the drainage bag; evaluation is indicated if there is suspected urosepsis 5
• Febrile infants and young children: Positive leukocyte esterase should prompt urine culture collection before initiating antimicrobial therapy 1, 6

Specimen Collection Guidelines

• For cooperative men: Midstream or clean-catch specimen 5
• For women: Often requires in-and-out catheterization for accurate results 5
• For catheterized patients: Aspiration from the catheter port, not the drainage bag 5
• Timing: Specimens should be examined within two hours of collection to prevent false results 3

Common Pitfalls to Avoid

• Treating asymptomatic bacteriuria: Asymptomatic bacteriuria with pyuria is common, especially in older adults (prevalence 15-50% in non-catheterized long-term care facility residents) 1, 6
• Relying solely on leukocyte esterase: When contamination has been excluded, leukocyturia in the absence of significant bacteriuria mandates further diagnostic evaluation 7
• Misinterpreting non-specific symptoms: Non-specific symptoms like confusion, falls, or functional decline alone should not trigger antibiotic treatment for presumed UTI 6
• Ignoring false positives/negatives: False-positive results can occur with contaminated specimens, certain oxidizing agents, and some medications 1

Interpretation of Leukocyturia Without Bacteriuria

• When contamination has been excluded, leukocyturia in the absence of significant bacteriuria requires further diagnostic evaluation 7
• Leukocytes may be differentiated into neutrophil or eosinophil granulocytes or lymphocytes, which can provide additional diagnostic information 7
• Consider other causes of sterile pyuria such as sexually transmitted infections, kidney stones, or interstitial nephritis 8