C-Reactive Protein
CRP
- Sample
- Blood
- Usual units
- mg/L
Also known as CRP · C Reactive Protein · hs-CRP · High Sensitivity CRP · Hs CRP
What this test measures
C-reactive protein is a protein made by the liver as part of the body's inflammatory response. A blood test measures its concentration, usually in milligrams per liter (mg/L).
Reading your report
There isn’t one standard range for this test — each lab prints its own. Use the range shown next to your result.
C-Reactive Protein unit converter
Convert C-Reactive Protein units
Labs print this test in mg/dL or mg/L depending on where the sample was run.
Related guides
- Guide
Why the same blood test has different "normal" ranges at different labs
Reference intervals are built from each lab's own population and equipment, which is why two labs can print different ranges for the same sample.
- Guide
Reference interval, cutoff, and the "optimal" numbers online: three different things
The range beside your result, the target a website quotes, and the threshold that defines a condition are built in different ways and answer different questions.
- Guide
Why the same lab printed a different reference range for you this year
Ranges are not fixed constants. The lab can change method, revise its reference group, or apply a range that depends on your age — none of which is an error.
- Guide
CRP and hs-CRP: two tests for one protein, used for different things
C-reactive protein rises with inflammation from any source. The high-sensitivity version measures the same protein at much smaller amounts, and the two are not interchangeable on a report.