What is the appropriate treatment for a urinary tract infection with a leukocyte esterase level of 75 leu/ul?

Treatment of Urinary Tract Infection with Leukocyte Esterase Level of 75 leu/μl

A positive leukocyte esterase test of 75 leu/μl alone is insufficient to diagnose a urinary tract infection (UTI) and requires additional clinical symptoms and/or positive nitrite test before initiating antibiotic therapy. 1

Diagnostic Criteria for UTI

A proper diagnosis of UTI requires:

1. Clinical symptoms AND
2. Laboratory evidence of infection:
   • Positive leukocyte esterase (≥5 leukocytes per high-power field) AND/OR
   • Positive nitrite test
   • Ideally confirmed with urine culture showing ≥50,000 CFU/mL of a single uropathogen 1

The leukocyte esterase test alone has:

• Sensitivity: 83% (67-94%)
• Specificity: 78% (64-92%) 1

When combined with nitrite testing, diagnostic accuracy improves:

• Combined sensitivity: 93% (90-100%)
• Combined specificity: 72% (58-91%) 1

Treatment Algorithm

Step 1: Confirm UTI diagnosis

• If symptomatic with positive leukocyte esterase (75 leu/μl): Proceed with treatment
• If asymptomatic with only positive leukocyte esterase: Do not treat (except in pregnancy) 1

Step 2: Select appropriate antibiotic

For uncomplicated UTI in adults with confirmed diagnosis:

1. First-line options (based on local resistance patterns):

   • Trimethoprim-sulfamethoxazole 1, 2
   • Nitrofurantoin
   • Cephalexin

2. Treatment duration:

   • Uncomplicated cystitis: 3-5 days
   • Complicated UTI or pyelonephritis: 7-14 days 1

Special Considerations

Elderly Patients

• Atypical presentations are common (confusion, falls, functional decline)
• Negative leukocyte esterase and nitrite often suggest absence of UTI 3
• Specificity of dipstick tests ranges from 20% to 70% in elderly 3
• Do not treat asymptomatic bacteriuria in elderly patients 3, 1

Algorithm for Frail/Elderly Patients

If patient has:

• Recent onset dysuria, frequency, urgency, or incontinence AND
• Positive leukocyte esterase or nitrite: Prescribe antibiotics

If patient has:

• Only non-specific symptoms (mental status changes, decreased appetite, etc.) WITHOUT
• Fever, rigors, or clear-cut delirium: Do not prescribe antibiotics 3

Common Pitfalls to Avoid

1. Treating based on laboratory findings alone: A positive leukocyte esterase test without symptoms does not warrant treatment 1

2. Ignoring alternative diagnoses: In women, consider vaginitis or urethritis which can present with similar symptoms 1

3. Misinterpreting contaminated samples: Proper collection techniques are essential for accurate diagnosis 1

4. Treating asymptomatic bacteriuria: This is common (10-50%) and should not be treated except in pregnancy 1

5. Relying solely on dipstick tests: These have limited sensitivity and specificity, particularly in elderly patients 3, 4

Follow-up Recommendations

• No routine follow-up urine cultures are needed if symptoms resolve 1
• Instruct patients to seek prompt medical evaluation (within 48 hours) for future febrile illnesses 1