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.
Related Inflammation tests
See all →ESR (Erythrocyte Sedimentation Rate)
Non-specific marker of inflammation — how fast red cells settle.
mm/hrInflammationHigh-Sensitivity CRP (hs-CRP)
Precise CRP measurement used for cardiovascular risk assessment.
mg/LInflammationProcalcitonin (PCT)
Blood marker that rises specifically in bacterial infection and sepsis.
ng/mLThis 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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