Diagnosis of urinary tract infection in children: fresh urine microscopy or culture?

Lancet. 1991 Sep 28;338(8770):767-70. doi: 10.1016/0140-6736(91)90662-9.


Fresh unspun and unstained urine specimens from 342 children with previous urinary tract infection (UTI) or symptoms compatible with a UTI were examined by microscopy at a magnification of x 400 in a mirrored counting chamber by a clinician, and sent for culture in a microbiology laboratory; 200 samples were also plated onto dip-slides. When microscopy and culture results were discrepant, further urine samples were collected until a diagnosis of UTI (24) or sterile urine (318) could be confirmed. Initial microscopy correctly identified 23 of 24 UTIs and 286 of 318 sterile urines; 1 false-positive result was caused by vaginal contamination with lactobacilli. 32 specimens (9%) gave an equivocal result on microscopy; the 1 other true-positive result was identified correctly on microscopy of the next urine specimen obtained. Culture of the initial urines correctly identified all 24 UTIs, but only 82% of the negative samples. Of the samples from uninfected children, 35 (11%) showed a mixed growth which was sterile on repeat sampling, and 21 (6.6%) initially grew a false-positive pure growth of more than 10(5) colony-forming units/ml of one organism. True UTIs were associated with bacterial counts above 10(7)/ml. Microscopy by a clinician represents a cheaper, quicker, and more reliable screening test for UTI in children than does routine culture in a microbiology laboratory.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial

MeSH terms

  • Adolescent
  • Algorithms
  • Child
  • Child, Preschool
  • Colony Count, Microbial / standards
  • False Positive Reactions
  • Female
  • Humans
  • Infant
  • Male
  • Microscopy
  • Microscopy, Phase-Contrast / standards
  • Prospective Studies
  • Recurrence
  • Sensitivity and Specificity
  • Time Factors
  • Urinary Tract Infections / diagnosis*
  • Urinary Tract Infections / microbiology
  • Urinary Tract Infections / urine