title: Protein C as an early biomarker to distinguish pneumonia from sepsis.
abstract: OBJECTIVE
  Patients with pneumonia often are unrecognized as also having sepsis. We evaluated protein C, as a potential biomarker, to differentiate between patients with pneumonia and sepsis.
  
  
  METHODS
  A retrospective chart review was performed for all protein C tests over a 14-month period (January 11, 2007, to March 10, 2008) at an 8-hospital system with 1706 total beds. Charts were screened for the discharge diagnoses of sepsis, severe sepsis, septic shock, bacteremia, and pneumonia. Protein C levels were compared between patients with sepsis and pneumonia, and at time intervals of 0 to 12 hours, 12 to 24 hours, 24 to 48 hours, and more than 48 hours after diagnosis.
  
  
  RESULTS
  One thousand forty-seven protein C levels were obtained in 980 patients. Thirty-two protein C levels met the inclusion and exclusion criteria for the sepsis group, and 34 for the pneumonia group. Overall, the mean protein C levels were significantly less in patients with sepsis at 59.2% (95% confidence interval [CI], 49.5%-68.9%) compared with patients with pneumonia at 108.9% (95% CI, 95.6%-122.3%; P < .001). In addition, levels within each of the time intervals were also significantly lower in the sepsis group.
  
  
  CONCLUSIONS
  In this study, protein C levels performed well in differentiating between patients with sepsis or pneumonia in the early period after diagnosis.
authors.affiliation: Department of Emergency Medicine, University of Kansas Hospital, Kansas City, KS 66160, USA. sgutovitz@kumc.edu
authors.forename: Scott
authors.initials: S
authors.lastname: Gutovitz
authors.forename: Linda
authors.initials: L
authors.lastname: Papa
authors.forename: Edgar
authors.initials: E
authors.lastname: Jimenez
authors.forename: Jay
authors.initials: J
authors.lastname: Falk
authors.forename: Leighann
authors.initials: L
authors.lastname: Wieman
authors.forename: Sandra
authors.initials: S
authors.lastname: Sawyer
authors.forename: Philip
authors.initials: P
authors.lastname: Giordano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000097:blood / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011486:Protein C / Q000032:analysis*; D012189:Retrospective Studies; D018805:Sepsis / Q000097:blood / Q000175:diagnosis*; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D011486:Protein C