What does 2+ leukocytes on an otherwise normal urinalysis indicate?

Interpretation of 2+ Leukocytes on an Otherwise Normal Urinalysis

The presence of 2+ leukocytes on an otherwise normal urinalysis is not sufficient to diagnose a urinary tract infection (UTI) without accompanying symptoms, and should not trigger antibiotic treatment in the absence of specific urinary symptoms. 1, 2

Diagnostic Significance of Isolated Leukocytes

• Leukocyte esterase testing has moderate sensitivity (83%, range 67-94%) but limited specificity (78%, range 64-92%) for detecting UTIs 1
• Isolated leukocyturia without other abnormal findings or symptoms may represent:
  • Asymptomatic bacteriuria, which is common especially in older adults (prevalence 15-50% in non-catheterized long-term care facility residents) 1
  • Early or resolving UTI 1
  • Non-infectious causes of sterile pyuria 2
• The absence of pyuria (negative leukocyte esterase and no microscopic WBCs) has excellent negative predictive value for ruling out UTI 1

Clinical Correlation Is Essential

• Leukocytes should be interpreted in conjunction with clinical symptoms such as dysuria, frequency, urgency, fever, or gross hematuria 1, 2
• When leukocytes are accompanied by a positive nitrite test, the specificity for UTI increases to 96% (combined sensitivity 93%) 1
• In asymptomatic individuals, urinalysis and urine cultures should not be performed routinely 1
• Non-specific symptoms like confusion or functional decline alone should not trigger UTI treatment without specific urinary symptoms in older adults 1, 2

Recommended Next Steps

• Assess for specific urinary symptoms (dysuria, frequency, urgency, suprapubic pain) 1, 2
• If symptomatic:
  • Obtain urine culture before starting antibiotics 2
  • Consider treatment based on culture results and symptoms 2
• If asymptomatic:
  • No further testing or treatment is needed 1, 2
  • Avoid treating based solely on the presence of leukocytes 2

Potential Alternative Diagnoses

• Contaminated specimen (common even with ideal collection technique) 3
• Viral cystitis (characterized by minimal bacterial inflammation, predominance of lymphocytes, epithelial cells, and few neutrophils) 4
• Non-infectious inflammation 2
• Partially treated UTI 1

Common Pitfalls to Avoid

• Treating asymptomatic bacteriuria leads to unnecessary antibiotic use and resistance 2
• Relying solely on dipstick results without considering clinical symptoms leads to overtreatment 2
• False-positive leukocyte esterase results can occur with contaminated specimens, certain oxidizing agents, and some medications 1
• Contemporary automated urinalysis indices are often abnormal in disease-free populations of women, even using ideal collection technique 3

Special Considerations

• In certain populations (e.g., children), the absence of pyuria may not exclude UTI in patients with compatible clinical findings 5
• Certain pathogens like Klebsiella spp. and Enterococcus spp. may cause UTI with less pronounced pyuria 5
• A cutoff value of 87.2 leukocytes/μL has been reported to have 98.33% sensitivity and 95% specificity for UTI diagnosis 6