CRP (C-reactive protein) is made by the liver in response to inflammation. It rises within hours of infection or injury. A high-sensitivity version (hs-CRP) measures low levels for heart risk.
- Normal range (adults)
- Up to 5 mg/L (up to 0.5 mg/dL)
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- C-Reactive Protein, C Reactive Protein, hsCRP, hs-CRP, High Sensitivity CRP, Highly Sensitive CRP
CRP normal range
| Group | mg/LConventional units: US, South Asia | mg/dLSI units: UK, Europe, Australia, international |
|---|---|---|
| Adults | Up to 5 | Up to 0.5 |
For heart-risk screening (hs-CRP): below 1 mg/L is low risk, 1–3 average, above 3 high.
Your report may use either unit system; labs in the Gulf often print both. Ranges also vary slightly between laboratories, so the range printed on your own report is the one to go by.
Why is the CRP test done?
It is used to detect infection and inflammation, monitor treatment, and (as hs-CRP) assess heart risk.
What does a high CRP level mean?
A high CRP means active inflammation. Over 10 mg/L usually points to infection or an inflammatory illness; mild rises (1 to 10 mg/L) are linked to overweight, smoking and higher heart risk.
Common causes
- Bacterial or viral infections
- Autoimmune and inflammatory diseases
- Injury or recent surgery
- Overweight, smoking and poor sleep (mild rises)
Diet and lifestyle tips
- Anti-inflammatory eating: vegetables, fruit, legumes, whole grains, oily fish, olive oil, nuts
- Limit sugar, refined flour, fried and processed foods
- Lose excess weight, stop smoking and stay active
- Treat any infection as your doctor advises
When should you see a doctor?
A very high CRP (above 100 mg/L) usually means significant infection and needs medical review.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.