Arch Dis Child Educ Pract Ed 95:55-58 doi:10.1136/adc.2009.174367
  • Interpretations

How to use: C-reactive protein

  1. A Riordan
  1. Department of Paediatric Infectious Diseases, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
  1. Correspondence to Dr Andrew Riordan, Alder Hey Children's NHS Foundation Trust, Eaton Road, Liverpool L12 2AP, UK; andrew.riordan{at}
  • Accepted 25 November 2009


C-reactive protein (CRP) is an acute-phase protein that increases 4–6 h after an inflammatory trigger and peaks at 36–50 h. Levels decrease rapidly with the resolution of inflammation. CRP is generally highly elevated in invasive bacterial infections and is often used as a marker of inflammation. A single CRP level is neither sensitive nor specific enough to identify all children with serious bacterial infection. However, a raised CRP does suggest serious bacterial infection and should suggest further assessment is needed. CRP levels that fail to decrease, or continue to rise, after 48 h of antibiotic therapy suggest treatment failure. In infants with suspected neonatal sepsis, two CRP measurements 24 h apart that are <10 mg/l are useful in excluding sepsis.


  • Competing interests None.

  • Provenance and peer review Commissioned; externally peer reviewed.

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