title: Performance of a bedside C-reactive protein test in the diagnosis of community-acquired pneumonia in adults with acute cough.
abstract: OBJECTIVE
  To evaluate the performance of a rapid, bedside whole blood C-reactive protein test as a diagnostic test for pneumonia in adults.
  
  
  METHODS
  We enrolled consecutive adults who presented with acute cough (duration < or =3 weeks). A fingerstick blood specimen for C-reactive protein level was obtained. Patients also provided information about demographic characteristics and symptoms. Physical examination findings, diagnoses, and treatments were abstracted from the medical record; illness duration and subsequent office visits were determined with follow-up telephone calls. A clinical prediction rule for pneumonia was calculated for each patient and compared with C-reactive protein levels.
  
  
  RESULTS
  Twenty (12%) of the 168 patients in the study had radiographic evidence of pneumonia. Median C-reactive protein levels were significantly higher for patients with pneumonia than in the remaining patients (60 mg/L vs. 9 mg/L, P <0.0001). The area under the receiver operating characteristic (ROC) curve for C-reactive protein level as a predictor of pneumonia was 0.83. C-reactive protein level and the clinical prediction rule were independently associated with pneumonia, yielding a combined area under the ROC curve of 0.93. C-reactive protein level was not associated with hospitalization or resolution of symptoms.
  
  
  CONCLUSIONS
  C-reactive protein levels could be a valuable addition to clinical prediction rules for pneumonia. A C-reactive protein level > or =100 mg/L might be a useful indication for chest radiography or empiric antibiotic therapy when the diagnosis of pneumonia is in doubt.
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of California, San Francisco 94118, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Flanders
authors.forename: John
authors.initials: J
authors.lastname: Stein
authors.forename: Guy
authors.initials: G
authors.lastname: Shochat
authors.forename: Karen
authors.initials: K
authors.lastname: Sellers
authors.forename: Miles
authors.initials: M
authors.lastname: Holland
authors.forename: Judith
authors.initials: J
authors.lastname: Maselli
authors.forename: W Lawrence
authors.initials: WL
authors.lastname: Drew
authors.forename: Art L
authors.initials: AL
authors.lastname: Reingold
authors.forename: Ralph
authors.initials: R
authors.lastname: Gonzales
mesh_terms: D000328:Adult; D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism*; D017714:Community-Acquired Infections / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D003371:Cough / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D012372:ROC Curve
chemical_list: D002097:C-Reactive Protein