title: Usefulness of procalcitonin for the diagnosis of ventilator-associated pneumonia.
abstract: OBJECTIVE
  To assess the predictive capacity for the diagnosis of ventilator-associated pneumonia (VAP) of serum procalcitonin levels before and on the day it is suspected.
  
  
  METHODS
  Single-center observational study in the intensive care unit of a teaching hospital.
  
  
  METHODS
  Consecutive patients whose serum procalcitonin levels were available on the day that VAP was clinically suspected (day 1) and at some time within the preceding 5 days ("before").
  
  
  RESULTS
  Serum procalcitonin levels were determined on day 1 and "before". Among the 73 suspected episodes VAP was confirmed by quantitative bronchoalveolar lavage cultures in 32 and refuted in 41. Respective median "before" procalcitonin levels were 1.89 ng/ml (interquartile range 0.18-6.01) and 2.14 (0.76-5.75) in patients with and without VAP, but their respective median day-1 procalcitonin levels did not differ: 1.07 ng/ml (0.39-6.57) vs. 1.40 (0.67-3.39). On day 1 a 0.5 ng/ml procalcitonin threshold had 72% sensitivity but only 24% specificity for diagnosing VAP. Between "before" and day 1, procalcitonin increased in 41% and 15% of patients with and without VAP, respectively. Thus a procalcitonin rise on day 1, compared to its "before" level, had 41% sensitivity and 85% specificity for diagnosing VAP, with respective positive and negative predictive values of 68% and 65%.
  
  
  CONCLUSIONS
  Crude values and procalcitonin rise had poor diagnostic value for VAP in this particular setting and thus should not be used to initiate antibiotics when VAP is clinically suspected.
authors.affiliation: Service de Réanimation Médicale, Groupe Hospitalier Pitié Salpêtrière, Université Paris 6, 75651, Paris Cedex 13, France. charles-edouard.luyt@psl.aphp.fr
authors.forename: Charles-Edouard
authors.initials: CE
authors.lastname: Luyt
authors.forename: Alain
authors.initials: A
authors.lastname: Combes
authors.forename: Catherine
authors.initials: C
authors.lastname: Reynaud
authors.forename: Guillaume
authors.initials: G
authors.lastname: Hekimian
authors.forename: Ania
authors.initials: A
authors.lastname: Nieszkowska
authors.forename: Marc
authors.initials: M
authors.lastname: Tonnellier
authors.forename: Alexandra
authors.initials: A
authors.lastname: Aubry
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Trouillet
authors.forename: Maguy
authors.initials: M
authors.lastname: Bernard
authors.forename: Jean
authors.initials: J
authors.lastname: Chastre
mesh_terms: D000368:Aged; D019540:Area Under Curve; D002116:Calcitonin / Q000097:blood* / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000097:blood* / Q000175:diagnosis; D011498:Protein Precursors / Q000097:blood* / Q000378:metabolism; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide