CRP (C-Reactive Protein)
A blood test that measures CRP, a protein that rises quickly with inflammation or infection.
Quick Summary
To check for infection or inflammation and to see how well treatment is working.
The amount of C-reactive protein in the blood. A high-sensitivity version (hs-CRP) estimates heart risk.
No preparation needed.
Overview
The liver makes more CRP within hours of infection or inflammation.
CRP changes faster than ESR, so it's useful for following infections.
What It Measures
CRP
Inflammation marker.
hs-CRP
Low-level inflammation linked with heart risk.
How It's Performed
- 01
Preparation
Usually no special preparation. Tell the staff about medicines you take.
- 02
Blood sample
A small amount of blood is taken from a vein in your arm with a thin needle.
- 03
Afterwards
Press on the spot for a minute. A small bruise is common; you can go back to normal activities.
Reference Ranges
Note: Normal ranges vary by laboratory. Consult your report for the specific reference used.
| Parameter | Typical Range (Adult) | Units |
|---|---|---|
| CRP | Less than 10 | mg/L |
| hs-CRP (low heart risk) | Less than 1 | mg/L |
Interpreting Results & Next Steps
Discuss with Doctor
A normal CRP doesn't rule out every illness. Normal ranges differ between laboratories, ages and sexes; always use the range printed on your report and ask your doctor what your results mean.
If values are High:
High CRP suggests infection (often bacterial) or inflammation such as arthritis or after surgery.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- C-Reactive Protein (CRP) Test(opens in a new tab) · MedlinePlus, US National Library of Medicine