title: Diagnostic usefulness of procalcitonin as a marker of bacteremia in patients with acute pyelonephritis.
abstract: BACKGROUND
  Acute pyelonephritis (APN) is one of the most common community-acquired infections and frequently accompanies bacteremia. The purpose of this study was to investigate the diagnostic role of procalcitonin in predicting bacteremia in patients with APN.
  
  
  METHODS
  We conducted a retrospective study of patients with APN who visited the emergency department (ED) at Samsung Medical Center, Seoul. Predictors of bacteremia were analyzed and receiver operating characteristics (ROC) curves were plotted for procalcitonin, C-reactive protein (CRP), and leukocytes.
  
  
  RESULTS
  During the study period, a total of 147 patients who had microbiologically proven APN and available initial procalcitonin concentrations were identified. Of these, bacteremia was present in 84 patients. Multivariate analysis showed that age, hypotension, and higher procalcitonin concentrations independently predicted the presence of bacteremia. Procalcitonin had better discriminative power than CRP, as reflected by area under the ROC curve analysis (0.746 [95% CI, 0.667-0.826] vs. 0.602 [95% CI, 0.509-0.694], p = 0.02). At a cut-off value of 1.63 μg/L, procalcitonin predicted bacteremia with a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 61.9, 81.0, 81.3, 61.4 and 70.1%, respectively.
  
  
  CONCLUSIONS
  Procalcitonin concentration could be used as a reliable marker to predict bacteremia in patients with APN in the ED.
authors.affiliation: Division of Infectious Diseases, Samsung Medical Center, Korea.
authors.forename: Young Eun
authors.initials: YE
authors.lastname: Ha
authors.forename: Cheol-In
authors.initials: CI
authors.lastname: Kang
authors.forename: Yu Mi
authors.initials: YM
authors.lastname: Wi
authors.forename: Doo Ryeon
authors.initials: DR
authors.lastname: Chung
authors.forename: Eun-Suk
authors.initials: ES
authors.lastname: Kang
authors.forename: Nam Yong
authors.initials: NY
authors.lastname: Lee
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Song
authors.forename: Kyong Ran
authors.initials: KR
authors.lastname: Peck
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D016470:Bacteremia / Q000097:blood / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011498:Protein Precursors / Q000097:blood*; D011704:Pyelonephritis / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide