Pathology Handbook

C-reactive Protein (CRP)



Clinical Indications

C-Reactive Protein (CRP) is the most sensitive acute phase protein and is the assay of choice in most situations when detection or monitoring of the acute phase response is required. CRP is specific for the acute phase response and unlike ESR is not elevated due to other causes. It has a rapid response time and will rise within two hours of acute insult (surgery, infection, etc.). CRP has a short half life (8 hours) and should peak and begin decreasing within 48 hours if no other inflammatory event occurs. It's catabolism is not affected by the type of inflammation.

Request Form

Request on ICE


On request. 

Turnaround Time

Same day




2 ml


Vacutainer gold top

Causes for Rejection

Unlabelled or incorrectly labelled sample

Reference Range

Adult: less than 8 mg/L

Up to 1 month: less than 6 mg/L

Most patients (90%) without organic disease have CRP levels less than 3mg/L and 99% have levels less than 10mg/L. Neonates are unable to induce CRP synthesis to the same extent and the neonatal reference range is lower.

Slightly higher CRP levels may be found in pregnancy, but any increase is usually within the reference range quoted.