C-reactive protein (CRP) High Sensitivity test is a blood test that measures the amount of a protein called C-reactive protein in your blood. C-reactive protein test measures general levels of inflammation in the body.
High levels of CRP are caused by infections and long-term diseases. But a CRP test cannot show where the inflammation is or what is causing it. Other tests are needed to find the cause and location.
Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm.
Purpose of the test
C-reactive protein (CRP) test is done to:
- Check for infection after surgery. Its levels normally rise within 2 to 6 hours of surgery and then go down by the third day after surgery. If levels stay elevated 3 days after surgery, an infection may be present.
- Keep track of infections and diseases that cause inflammation, such as:
- Cancer of the lymph nodes (lymphoma).
- Diseases of the immune system.
- Painful swelling of the blood vessels in the head and neck.
- Rheumatoid arthritis.
- Swelling and bleeding of the intestines (inflammatory bowel).
- Bone infection.
- Check to see how treatment is working, such as treatment for cancer or for an infection. CRP levels go up and then become normal quickly if you are responding to treatment measures.
A special type of CRP test, the high-sensitivity CRP test (hs-CRP), may be done to find out if you have an increased chance of having a sudden heart problem, such as a heart attack. Inflammation can damage the inner lining of the arteries and make a heart attack more likely.
Reference range values
CRP <10 mg/L
<10 mg/L => Lowest risk
10 to 30 mg/L => Average risk
>30 mg/L => Highest risk
Any condition that results in sudden or severe inflammation may increase CRP levels.
Some medicines may decrease CRP levels.