title: Procalcitonin: a valuable indicator of infection in a medical ICU?
abstract: OBJECTIVE
  To assess the use of procalcitonin (PCT) for the diagnosis of infection in a medical ICU.
  
  
  METHODS
  Prospective, observational study.
  
  
  METHODS
  Seventy-seven infected patients and 24 patients with systemic inflammatory response syndrome (SIRS) due to other causes. Seventy-five patients could be classified into sepsis (n = 24), severe sepsis (n = 27) and septic shock (n = 24), and 20 SIRS patients remained free from infection during the study. Plasma PCT and C-reactive protein (CRP) levels were evaluated within 48 h of admission (day 0), at day 2 and day 4.
  
  
  RESULTS
  As compared with SIRS, PCT and CRP levels at day 0 were higher in infected patients, regardless of the severity of sepsis (25.2 +/- 54.2 ng/ml vs 4.8 +/- 8.7 ng/ml; 159 +/- 92 mg/l vs 71 +/- 58 mg/l, respectively). At cut-off values of 2 ng/ml (PCT) and 100 mg/l (CRP), sensitivity and specificity were 65% and 70% (PCT), 74% and 74% (CRP). PCT and CRP levels were significantly more elevated in septic shock (38.5 +/- 59.1 ng/ml and 173 +/- 98 mg/l) than in SIRS (3.8 +/- 6.9 ng/ml and 70 +/- 48 mg/l), sepsis (1.3 +/- 2.7 ng/ml and 98 +/- 76 mg/l) and severe sepsis (9.1 +/- 18. 2 ng/ml and 145 +/- 70 mg/l) (all p = 0.005). CRP, but not PCT, levels were more elevated in severe sepsis than in SIRS (p<0.0001). Higher PCT levels in the patients with four dysfunctional organs and higher PCT and CRP levels in nonsurvivors may only reflect the marked inflammatory response to septic shock.
  
  
  CONCLUSIONS
  In this study, PCT and CRP had poor sensitivity and specificity for the diagnosis of infection. PCT did not clearly discriminate SIRS from sepsis or severe sepsis.
authors.affiliation: Service de Réanimation Médicale, CHRU Pontchaillou, Rennes, France.
authors.forename: E
authors.initials: E
authors.lastname: Suprin
authors.forename: C
authors.initials: C
authors.lastname: Camus
authors.forename: A
authors.initials: A
authors.lastname: Gacouin
authors.forename: Y
authors.initials: Y
authors.lastname: Le Tulzo
authors.forename: S
authors.initials: S
authors.lastname: Lavoue
authors.forename: A
authors.initials: A
authors.lastname: Feuillu
authors.forename: R
authors.initials: R
authors.lastname: Thomas
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D016009:Chi-Square Distribution; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000097:blood* / Q000175:diagnosis; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D006023:Glycoproteins; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide