C-Reactive Protein (CRP)
CRP is a protein produced by the liver in response to inflammation anywhere in the body. It rises rapidly — within hours of inflammation onset — and falls quickly when inflammation resolves. CRP is a non-specific marker; it tells you inflammation exists but not where or why. High-sensitivity CRP (hs-CRP) is a variant used specifically for cardiovascular risk assessment.
Reference Ranges
Male
0 – 10
mg/L
Female
0 – 10
mg/L
Child
0 – 10
mg/L
Ages 1–18
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low CRP is normal and desirable — it indicates no significant inflammation in the body. hs-CRP below 1 mg/L indicates low cardiovascular risk.
What High Levels Mean
CRP above 10 mg/L usually indicates acute infection or significant inflammation. Very high CRP (>100 mg/L) suggests bacterial infection, major trauma, or autoimmune flare. For cardiovascular risk (hs-CRP): below 1 is low risk, 1–3 is average, above 3 is high risk.
Frequently Asked Questions
What is the difference between CRP and hs-CRP?
They measure the same protein but at different sensitivities. Standard CRP detects levels above 10 mg/L — useful for tracking infections and inflammatory diseases. High-sensitivity CRP (hs-CRP) detects much lower levels (0.1–10 mg/L) and is used specifically for cardiovascular risk assessment.
Can CRP identify where the infection is?
No. CRP only tells you that inflammation exists somewhere in the body — it cannot localize it. A high CRP requires additional tests (blood culture, imaging, etc.) to identify the source. However, serial CRP measurements are useful for monitoring treatment response.
Should I get hs-CRP tested for heart risk?
hs-CRP adds useful information for people at intermediate cardiovascular risk (10-year risk of 10–20%). If your risk is clearly low or clearly high based on cholesterol and blood pressure, hs-CRP may not change management. Discuss with your doctor whether it is appropriate for you.
This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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