title: C-reactive protein. A clinical marker in community-acquired pneumonia.
abstract: OBJECTIVE
  To assess the range of plasma C-reactive protein (CRP) in patients presenting with community-acquired pneumonia and to compare the serial changes of this acute-phase protein with clinical outcome.
  
  
  METHODS
  Prospective hospital-based study, including separate retrospective case series.
  
  
  METHODS
  Twenty-eight consecutive patients (mean age, 60 years) admitted to our hospital with community-acquired pneumonia were studied. Serial daily plasma samples were taken and assayed for CRP, tumor necrosis factor-alpha (TNF-alpha), and interleukin 6 (IL-6). Clinical parameters, laboratory data, and response to treatment were recorded. Four other patients considered to be antibiotic failures (three empyemas, one death) were studied separately.
  
  
  RESULTS
  Two patients died. Of those who survived, mean (+/- SD) CRP values for days 1,2,3,4, and 5 were as follows: 136 +/- 43, 96 +/- 44, 53 +/- 36, 54 +/- 43, and 44 +/- 31 mg/L. CRP levels on day 1 in patients who had received antibiotics prior to hospital admission were significantly lower than those who had not, 107 +/- 42 and 152 +/- 44 mg/L (p < 0.05). CRP levels did not correlate with other laboratory parameters or with recognized predictors of mortality. A CRP value that continued to rise despite antibiotic treatment was associated with infective complications or death. Only 52% of patients had detectable TNF-alpha and 24% detectable IL-6 at some point during their hospital stay.
  
  
  CONCLUSIONS
  CRP is a sensitive marker of pneumonia. A persistently high or rising CRP level suggests antibiotic treatment failure or the development of an infective complication. These results suggest that CRP, rather than TNF-alpha or IL-6, may have a role as a clinical marker in pneumonia.
authors.affiliation: Department of Respiratory Medicine, King's Cross Hospital, Dundee, United Kingdom.
authors.forename: R P
authors.initials: RP
authors.lastname: Smith
authors.forename: B J
authors.initials: BJ
authors.lastname: Lipworth
authors.forename: I A
authors.initials: IA
authors.lastname: Cree
authors.forename: E M
authors.initials: EM
authors.lastname: Spiers
authors.forename: J H
authors.initials: JH
authors.lastname: Winter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D017714:Community-Acquired Infections / Q000097:blood / Q000188:drug therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000097:blood* / Q000188:drug therapy; D011446:Prospective Studies; D017211:Treatment Failure
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D002097:C-Reactive Protein