title: Diagnostic value of serum procalcitonin in patients with chronic renal insufficiency: a systematic review and meta-analysis.
abstract: BACKGROUND
  The diagnostic value of procalcitonin (PCT) for patients with renal impairment is unclear.
  
  
  METHODS
  We searched multiple databases for studies published through December 2011 that evaluated the diagnostic performance of PCT among patients with renal impairment and suspected systemic bacterial infection. We summarized test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic (HSROC) curves, and bivariate random effects models.
  
  
  RESULTS
  Our search identified 201 citations, of which seven diagnostic studies evaluated 803 patients and 255 bacterial infection episodes. HSROC-bivariate pooled sensitivity estimates were 73% [95% confidence interval (95% CI) 54-86%] for PCT tests and 78% (95% CI 52-92%) for CRP tests. Pooled specificity estimates were higher for both PCT and CRP tests [PCT, 88% (95% CI 79-93%); CRP, 84% (95% CI, 52-96%)]. The positive likelihood ratio for PCT [likelihood (LR)+ 6.02, 95% CI 3.16-11.47] was sufficiently high to be qualified as a rule-in diagnostic tool, while the negative likelihood ratio was not low enough to be used as a rule-out diagnostic tool (LR- 0.31, 95% CI 0.17-0.57). There was no consistent evidence that PCT was more accurate than CRP test for the diagnosis of systemic infection among patients with renal impairment.
  
  
  CONCLUSIONS
  Both PCT and CRP tests have poor sensitivity but acceptable specificity in diagnosing bacterial infection among patients with renal impairment. Given the poor negative likelihood ratio, its role as a rule-out test is questionable.
authors.affiliation: Department of Critical Care Medicine, Hunan Children's Hospital, Changsha, Hunan Province, China.
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Lu
authors.forename: Zheng-Hui
authors.initials: ZH
authors.lastname: Xiao
authors.forename: Mei-Yu
authors.initials: MY
authors.lastname: Yang
authors.forename: Yi-Min
authors.initials: YM
authors.lastname: Zhu
mesh_terms: D001424:Bacterial Infections / Q000097:blood* / Q000175:diagnosis; D002097:C-Reactive Protein / Q000032:analysis*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D006801:Humans; D011498:Protein Precursors / Q000097:blood*; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000175:diagnosis; D012680:Sensitivity and Specificity
chemical_list: C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide