LAB TEST
C-reactive protein
C-reactive protein (CRP) is produced by the liver. The level of CRP rises when there is inflammation in the body. It is one of a group of proteins, called acute phase reactants that go up in response to inflammation. The levels of acute phase reactants increase in response to certain inflammatory proteins called cytokines. These proteins are produced by white blood cells during inflammation. This article discusses the blood test done to measure the amount of CRP in your blood.
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. Others may 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. This means it can reveal that you have inflammation somewhere in your body, but it cannot pinpoint the exact location or reason. The CRP test is often done with the ESR (erythrocyte or sedimentation rate) test which also…
Normal Results
Normal CRP values vary from lab to lab. The levels often increase slightly with age, female sex and in African Americans. The majority of healthy adults have levels less than 0.3 mg/dL. However, a low CRP level does not always mean that there is no inflammation present. Levels of CRP may not be increased in people…
What Abnormal Results Mean
It is unclear if a minor rise of 0.3 to 1 mg/dL in CRP levels is a cause for concern. The hs-CRP is more precise and may be used to further understand these results. CRP levels from 1 mg/dL to 10 mg/dL are thought to be a moderate increase. CRP Levels greater than 10 mg/dL are considered a marked increase. A positive…
Risks
Risks associated with having blood drawn are slight, but may include: Excessive bleeding Fainting or feeling lightheaded Hematoma (blood accumulating under the skin) Infection (a slight risk any time the skin is broken)
References
Dietzen DJ, Willrich MAV. Amino acids, peptides, and proteins. In: Rifai N, Chiu RWK, Young I, Burnham CD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine . 7th ed. St Louis, MO: Elsevier; 2023:chap 31. Haberman R, Fors Nieves CE, Cronstein BN, Saxena A. Acute phase reactants. In: Firestein GS, Budd RC, Gabriel…
This is a summary. Read the full article at www.ucsfbenioffchildrens.org (reviewed 25/01/2023).
This page is general information and is not medical advice. It does not replace a registered doctor, and it is not a prescription or a recommendation to use any medicine or test. Prices are listed prices and may change. Always follow the advice of your doctor or pharmacist.