C-reactive protein testing does not decrease antibiotic use for acute cough illness when compared to a clinical algorithm

J Emerg Med. 2011 Jul;41(1):1-7. doi: 10.1016/j.jemermed.2008.06.021. Epub 2008 Dec 17.


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.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Algorithms
  • Anti-Bacterial Agents / therapeutic use*
  • Biomarkers / blood
  • C-Reactive Protein / analysis*
  • Emergency Service, Hospital
  • Female
  • Hospitals, Urban
  • Humans
  • Male
  • Middle Aged
  • Point-of-Care Systems
  • Respiratory Tract Infections / diagnosis*
  • Respiratory Tract Infections / drug therapy*
  • United States
  • Young Adult


  • Anti-Bacterial Agents
  • Biomarkers
  • C-Reactive Protein