title: Diagnostic accuracy of the urinalysis for urinary tract infection in infants <3 months of age.
abstract: BACKGROUND
  The 2011 American Academy of Pediatrics urinary tract infection (UTI) guideline suggests incorporation of a positive urinalysis (UA) into the definition of UTI. However, concerns linger over UA sensitivity in young infants. Infants with the same pathogenic organism in the blood and urine (bacteremic UTI) have true infections and represent a desirable population for examination of UA sensitivity.
  
  
  METHODS
  We collected UA results on a cross-sectional sample of 276 infants <3 months of age with bacteremic UTI from 11 hospital systems. Sensitivity was calculated on infants who had at least a partial UA performed and had ≥50 000 colony-forming units per milliliter from the urine culture. Specificity was determined by using a random sample of infants from the central study site with negative urine cultures.
  
  
  RESULTS
  The final sample included 245 infants with bacteremic UTI and 115 infants with negative urine cultures. The sensitivity of leukocyte esterase was 97.6% (95% confidence interval [CI] 94.5%-99.2%) and of pyuria (>3 white blood cells/high-power field) was 96% (95% CI 92.5%-98.1%). Only 1 infant with bacteremic UTI (Group B Streptococcus) and a complete UA had an entirely negative UA. In infants with negative urine cultures, leukocyte esterase specificity was 93.9% (95% CI 87.9 - 97.5) and of pyuria was 91.3% (84.6%-95.6%).
  
  
  CONCLUSIONS
  In young infants with bacteremic UTI, UA sensitivity is higher than previous reports in infants with UTI in general. This finding can be explained by spectrum bias or by inclusion of faulty gold standards (contaminants or asymptomatic bacteriuria) in previous studies.
authors.affiliation: Department of Pediatrics, Santa Clara Valley Medical Center, San Jose, California; Alan.Schroeder@hhs.sccgov.org.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Schroeder
authors.affiliation: Department of Pediatrics, Kaiser Permanente Northern California, Oakland, California;
authors.forename: Pearl W
authors.initials: PW
authors.lastname: Chang
authors.affiliation: Department of Pediatrics, Dell Children's Medical Center, Austin, Texas; and.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Shen
authors.affiliation: Department of Pediatrics, University of Rochester, Rochester, New York.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Biondi
authors.affiliation: Department of Pediatrics, Kaiser Permanente Northern California, Oakland, California;
authors.forename: Tara L
authors.initials: TL
authors.lastname: Greenhow
mesh_terms: D016470:Bacteremia / Q000150:complications / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012680:Sensitivity and Specificity; D016482:Urinalysis; D014552:Urinary Tract Infections / Q000150:complications / Q000175:diagnosis* / Q000652:urine*