title: Pitfalls of diagnosing urinary tract infection in infants and young children.
abstract: BACKGROUND
  The aim of this study was to examine the sensitivity and specificity of pyuria-based diagnosis of urinary tract infection (UTI) in urine collected by transurethral catheterization, and the reliability of diagnosis of pyuria in urine collected in a perineal bag. The gold standard for UTI diagnosis is significant colony counts of a single organism in urine obtained in a sterile manner.
  
  
  METHODS
  We enrolled 301 patients who underwent medical examination at the present hospital for possible UTI between January 2005 and December 2009. We collected 438 urine samples by transurethral catheterization. We investigated the accuracy of pyuria-based diagnosis of UTI using transurethral catheterization urine specimens, and the reliability of diagnosis of pyuria using bag-collected urine specimens.
  
  
  RESULTS
  The false-negative rate of UTI diagnosis based on pyuria in transurethral catheterization urine sediments was 9.0%; there was no significant difference in the false-negative rate of UTI diagnosis between boys and girls. Approximately 28% of pyuria-positive bag-collected urine specimens were pyuria negative on transurethral catheterization; this rate was significantly higher in girls than in boys (56.7% vs. 8.9%, P < 0.0001).
  
  
  CONCLUSIONS
  The absence of pyuria in transurethral catheterization urine sediments does not rule out UTI. Pyuria in bag-collected urine specimens frequently consists of urine leukocytes from external genitalia as well as from the urinary tract.
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Yasuhito
authors.identifier: http://orcid.org/0000-0003-2857-9950
authors.initials: Y
authors.lastname: Yamasaki
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Uemura
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Takuhito
authors.initials: T
authors.lastname: Nagai
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Satoshi
authors.identifier: http://orcid.org/0000-0001-9782-7415
authors.initials: S
authors.lastname: Yamakawa
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Hibi
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, Obu, Aichi, Japan.
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Kasahara
authors.affiliation: Department of Biochemistry, Fukuoka University School of Medicine, Jonanku, Fukuoka, Japan.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Bo
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005188:False Negative Reactions; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis* / Q000652:urine; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis* / Q000652:urine; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011776:Pyuria / Q000175:diagnosis / Q000652:urine; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014546:Urinary Catheterization; D014552:Urinary Tract Infections / Q000175:diagnosis* / Q000652:urine; D055815:Young Adult
keywords: accuracy of pyuria diagnosis; diagnosis of urinary tract infection; false-negative rate; urine collected by catheterization; urine collected using a urine bag