Urinalysis Results That Indicate Treatment for UTI

Diagnostic Criteria for UTI

The American Academy of Pediatrics recommends that UTI should be treated when there is both a positive urinalysis showing evidence of infection and a positive urine culture with at least 50,000 CFU/mL of a uropathogen from a properly collected specimen 1
Pyuria is defined as ≥10 WBCs/high-power field on microscopic examination, according to the Journal of the American Geriatrics Society 2
Positive leukocyte esterase on dipstick testing is a diagnostic criterion for UTI, as recommended by the American Academy of Pediatrics 1
Positive nitrite test on dipstick testing is also a diagnostic criterion for UTI, as recommended by the American Academy of Pediatrics 1
Microscopy positive for bacteria is a diagnostic criterion for UTI, as recommended by the American Academy of Pediatrics 1

The American Academy of Family Physicians recommends that urine culture should show growth of ≥50,000 CFU/mL of a uropathogen, with a previous threshold of 100,000 CFU/mL 3, 1
The American Academy of Family Physicians recommends that specimen should be collected via catheterization or suprapubic aspiration for definitive diagnosis 4

If urinalysis shows positive leukocyte esterase OR positive nitrite OR microscopy positive for WBCs OR bacteria, the American Academy of Family Physicians recommends proceeding to urine culture 5
If urinalysis of fresh urine is negative for leukocyte esterase AND nitrites, UTI is unlikely (<0.3%) and can be followed clinically without antimicrobial therapy, according to the American Academy of Family Physicians 3, 5

In residents with chronic indwelling urinary catheters, bacteriuria and pyuria are virtually universal and not necessarily indicative of symptomatic infection, as noted by the Journal of the American Geriatrics Society 2
For residents with suspected urosepsis, catheters should be changed prior to specimen collection and antibiotic therapy, as recommended by the Journal of the American Geriatrics Society 2
Minimum laboratory evaluation should include urinalysis for leukocyte esterase, nitrite, and microscopic examination for WBCs, according to the Journal of the American Geriatrics Society 2
Only if pyuria (≥10 WBCs/high-power field) or positive leukocyte esterase or nitrite test is present should a urine culture be ordered, as recommended by the Journal of the American Geriatrics Society 2

The leukocyte esterase test has a sensitivity of 83% (67-94%) and specificity of 78% (64-92%), as reported in Pediatrics 7
The nitrite test has a sensitivity of 53% (15-82%) and specificity of 98% (90-100%), as reported in Pediatrics 7
The combined leukocyte esterase or nitrite positive test has a sensitivity of 93% (90-100%) and specificity of 72% (58-91%), as reported in Pediatrics 7
Microscopy for WBCs has a sensitivity of 73% (32-100%) and specificity of 81% (45-98%), as reported in Pediatrics 7
Microscopy for bacteria has a sensitivity of 81% (16-99%) and specificity of 83% (11-100%), as reported in Pediatrics 7

The Journal of the American Geriatrics Society recommends not treating asymptomatic bacteriuria in most populations, as it does not increase morbidity or mortality 2
The American Academy of Family Physicians recommends not relying solely on symptoms for diagnosis, as more pronounced symptoms do not correlate with significant bacteriuria 5
The Annals of Emergency Medicine recommends not using bag urine specimens for culture due to high contamination rates (85% false positive rate with bagged specimens) 8
The Journal of the American Geriatrics Society recommends not assuming all positive cultures represent infection - distinguish UTI from asymptomatic bacteriuria, especially in catheterized patients 2
The American Academy of Family Physicians recommends not starting antibiotics before obtaining urine specimens, as most agents will sterilize the urine rapidly, obscuring diagnosis 4

The American Academy of Family Physicians recommends that treatment should be guided by local antibiotic susceptibility patterns 5