C-reactive protein (CRP) is produced by the liver. The level of CRP rises when there is inflammation throughout the body. It is one of a group of proteins called "acute phase reactants" that go up in response to inflammation.
This article discusses the blood test done to measure the amount of CRP in your blood.
CRP; High-sensitivity C-reactive protein; hs-CRP
How the Test is Performed
A blood sample is needed. This is most often taken from a vein. The procedure is called a venipuncture.
How to Prepare for the Test
No special steps are needed to prepare for this test.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
The CRP test is a general test to check for inflammation in the body. It is not a specific test. That means it can reveal that you have inflammation somewhere in your body, but it cannot pinpoint the exact location. The CRP test is often done with the ESR or sed rate test which also looks for inflammation.
Note: Positive CRP results also occur during the last half of pregnancy or with the use of birth control pills (oral contraceptives).
Risks associated with having blood drawn are slight but may include:
Fainting or feeling light-headed
Hematoma (blood accumulating under the skin)
Infection (a slight risk any time the skin is broken)
Ridker PM, Libby P, Buring JE. Risk markers and the primary prevention of cardiovascular disease. In: Mann DL, Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 39.
Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.