title: Discolored ureteral stents: findings in urinalysis and urine culture.
abstract: OBJECTIVE
  Discolored ureteral stents are sometimes encountered in daily clinical practice; however, the mechanism(s) underlying the development of discolored ureteral stents remain unknown. In this study, we retrospectively analyzed the characteristics of discolored ureteral stents based on the results of a urinalysis and urine culture.
  
  
  METHODS
  We identified a total of 26 patients with discolored ureteral stents and compared the findings in the urinalyses and urine culture in 21 discolored versus 45 non-colored ureteral stents.
  
  
  RESULTS
  The median and mean (± SD) duration of stenting time was 78.0 and 81.3 (± 21.3) days for the discolored ureteral stents and 69.0 and 74.9 (± 19.8) days for the non-colored ureteral stents, respectively (P = 0.25). The discolored ureteral stents were associated with a higher mean urine pH than the non-colored ureteral stents (mean: 6.4 vs 6.0, P< 0.05). There were no significant differences between the two groups in the RBC (P = 0.51) and WBC (P = 0.35) counts in the urinalyses. In addition, the rate of a positive culture in the patients with discolored stents [20 of 21 (95.2%)] was significantly (P <0.01) higher than that observed in the patients with non-colored ureteral stents [33 of 45 (73.3%)].
  
  
  CONCLUSIONS
  In this study, the subjects with discolored ureteral stents showed a significantly higher likelihood of having a positive urine culture and also demonstrated higher pH values in the urinalyses. However, no clear cut-off point to predict discoloration was indicated.
authors: Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan; Department of Urology, Ohguchi Higashi General Hospital, Yokohama, Kanagawa, Japan; Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
authors: Takashi
authors: T
authors: Kawahara
authors: Departments of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
authors: Hiroshi
authors: H
authors: Miyamoto
authors: Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan; Department of Urology, Ohguchi Higashi General Hospital, Yokohama, Kanagawa, Japan.
authors: Hiroki
authors: H
authors: Ito
authors: Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan; Department of Urology, Ohguchi Higashi General Hospital, Yokohama, Kanagawa, Japan.
authors: Hideyuki
authors: H
authors: Terao
authors: Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan.
authors: Hiroji
authors: H
authors: Uemura
authors: Department of Urology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan.
authors: Yoshinobu
authors: Y
authors: Kubota
authors: Department of Urology, Ohguchi Higashi General Hospital, Yokohama, Kanagawa, Japan.
authors: Junichi
authors: J
authors: Matsuzaki
mesh_terms: D003116:Color; D046508:Culture Techniques; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015607:Stents; D013997:Time Factors; D014513:Ureter; D016482:Urinalysis; D014556:Urine / Q000737:chemistry*