Use of Urinary Gram Stain for Detection of Urinary Tract Infection in Infants

Ann Emerg Med. 1995 Jan;25(1):31-5. doi: 10.1016/s0196-0644(95)70351-9.


Study objective: To determine whether Gram stain of urine is more sensitive than urinalysis in detecting urinary tract infection in infants.

Design: Prospective series.

Setting: Urban teaching hospital emergency department.

Participants: Two hundred seven infants 6 months old or less, from whom a catheterized or suprapubically aspirated urine specimen was obtained for culture.

Interventions: Urinary Gram stain, culture, and urinalysis were performed. With culture results as the validating standard, the Gram stain sensitivity, specificity, and predictive values were compared with urinalysis, including leukocyte esterase, nitrite, pyuria, and bacteriuria.

Results: The prevalence of positive cultures was 8.7% (18 of 207). Gram stain had higher sensitivity than overall urinalysis (94% versus 67%, P < .05), higher specificity (92% versus 79%, P < .05), and higher positive predictive value (53% versus 23%, P < .05).

Conclusion: Urinary Gram stain appears to be more reliable than urinalysis in detecting urinary tract infection in young infants.

MeSH terms

  • Bacteriuria / microbiology
  • Bacteriuria / urine*
  • Emergency Service, Hospital
  • Female
  • Humans
  • Infant
  • Male
  • Predictive Value of Tests
  • Prospective Studies
  • Sensitivity and Specificity
  • Staining and Labeling
  • Urinalysis / methods*
  • Urinary Tract Infections / diagnosis
  • Urinary Tract Infections / urine
  • Urine / microbiology