What this marker measures
Standard CRP and high-sensitivity CRP (hs-CRP) are different tests. Standard CRP detects significant inflammation (infections, flares); hs-CRP measures very low-level chronic inflammation and is used to assess long-term cardiovascular risk. The same protein is measured — just at different sensitivities.
High or low: what it can mean
High CRP
Elevated CRP indicates there is active inflammation or infection somewhere in the body. Significantly raised values (above 100 mg/L) often point to bacterial infection; milder elevations have many causes including viral infection, autoimmune conditions, and injury.
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Low CRP
CRP below normal reference values or undetectable simply means there is no active significant inflammatory process at the time of testing.
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Lifestyle considerations
- •Maintaining a healthy weight, exercising regularly, quitting smoking, and following a Mediterranean-style diet are associated with lower hs-CRP over time
Frequently asked questions
What is CRP?
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CRP is a protein produced by the liver in response to inflammation anywhere in the body. It rises rapidly within hours of an inflammatory stimulus and falls quickly when the cause resolves.
What does CRP measure?
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Standard CRP and high-sensitivity CRP (hs-CRP) are different tests. Standard CRP detects significant inflammation (infections, flares); hs-CRP measures very low-level chronic inflammation and is used to assess long-term cardiovascular risk. The same protein is measured — just at different sensitivities.
What does high CRP mean?
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Elevated CRP indicates there is active inflammation or infection somewhere in the body. Significantly raised values (above 100 mg/L) often point to bacterial infection; milder elevations have many causes including viral infection, autoimmune conditions, and injury.
What does low CRP mean?
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CRP below normal reference values or undetectable simply means there is no active significant inflammatory process at the time of testing.
What supports healthy CRP levels?
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Maintaining a healthy weight, exercising regularly, quitting smoking, and following a Mediterranean-style diet are associated with lower hs-CRP over time
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.