title: C-reactive protein testing does not decrease antibiotic use for acute cough illness when compared to a clinical algorithm.
abstract: BACKGROUND
  Antibiotics are commonly overused in adults seeking emergency department (ED) care for acute cough illness.
  
  
  OBJECTIVE
  To evaluate the effect of a point-of-care C-reactive protein (CRP) blood test on antibiotic treatment of acute cough illness in adults.
  
  
  METHODS
  A randomized controlled trial was conducted in a single urban ED in the United States. The participants were adults (age ≥ 18 years) seeking care for acute cough illness (≤ 21 days duration); 139 participants were enrolled, and 131 completed the ED visit. Between November 2005 and March 2006, study participants had attached to their medical charts a clinical algorithm with recommendations for chest X-ray study or antibiotic treatment. For CRP-tested patients, recommendations were based on the same algorithm plus the CRP level.
  
  
  RESULTS
  There was no difference in antibiotic use between CRP-tested and control participants (37% [95% confidence interval (CI) 29-45%] vs. 31% [95% CI 23-39%], respectively; p = 0.46) or chest X-ray use (52% [95% CI 43-61%] vs. 48% [95% CI 39-57%], respectively; p = 0.67). Among CRP-tested participants, those with normal CRP levels received antibiotics much less frequently than those with indeterminate CRP levels (20% [95% CI 7-33%] vs. 50% [95% CI 32-68%], respectively; p = 0.01).
  
  
  CONCLUSIONS
  Point-of-care CRP testing does not seem to provide any additional value beyond a point-of-care clinical decision support for reducing antibiotic use in adults with acute cough illness.
authors.affiliation: Department of Medicine, University of California, San Francisco, San Francisco, California 94118, USA.
authors.forename: Ralph
authors.initials: R
authors.lastname: Gonzales
authors.forename: Eva M
authors.initials: EM
authors.lastname: Aagaard
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
authors.forename: O John
authors.initials: OJ
authors.lastname: Ma
authors.forename: Mark
authors.initials: M
authors.lastname: Plautz
authors.forename: Judith H
authors.initials: JH
authors.lastname: Maselli
authors.forename: Charles E
authors.initials: CE
authors.lastname: McCulloch
authors.forename: Sara K
authors.initials: SK
authors.lastname: Levin
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Metlay
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D004636:Emergency Service, Hospital; D005260:Female; D006786:Hospitals, Urban; D006801:Humans; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000188:drug therapy*; D014481:United States; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D002097:C-Reactive Protein