CRP
A general marker of inflammation — raised by infection, injury or inflammatory disease, without saying which.
What it means
A protein made by the liver in response to inflammation anywhere in the body. It rises within hours and falls quickly once the cause settles.
It is entirely non-specific. A raised CRP is consistent with a chest infection, a flare of arthritis, a recent injury, a dental abscess or a hundred other things. It says something is inflamed, not what.
A normal CRP does not exclude serious illness, and this is worth knowing — some significant conditions run with a normal one.
In practice
On almost every hospital and GP blood panel. It is one of the most frequently requested tests in medicine.
hs-CRP — high sensitivity CRP — is a more precise version used on health screens as part of cardiovascular risk assessment rather than to detect infection.
Why it matters
Interpret it alongside how you feel, not on its own. A mildly raised CRP in someone who is entirely well is usually nothing; a normal CRP in someone who is very unwell should not reassure anyone.
Ask what the number is being compared with — the direction of travel across two results is more useful than a single figure.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026