What Is a CRP Blood Test?

A CRP blood test, also known as a C-reactive protein test, is designed to measure the level of C-reactive protein in the bloodstream. C-reactive protein is a marker that indicates general levels of inflammation in the body, according to WebMD.

According to WebMD, a normal CRP level is less than 10 milligrams per liter. However, a doctor needs to evaluate CRP test results within the context of a patient's overall health as well as other medical factors.

A CRP test can be done after a surgical procedure to ensure that no infection is present, notes WebMD. Levels of the protein usually increase anywhere from two to six hours after the surgery is complete and decrease by the third day after the procedure. In the event that CRP levels remain high after three days, there is a chance the patient has an infection.

Any condition that causes inflammation in the body can cause an elevated CRP results. These conditions include infections as well as long term diseases, states WebMD.

A special CRP test, called a high-sensitivity CRP test, indicates the chances of an individual experiencing a stroke or heart attack, notes WebMD. Doctors use the results of this high-sensitivity CRP to outline steps to take to mitigate the risks of the person suffering from a stroke or heart attack.

One limitation of the C-reactive protein test is that it cannot determine where the inflammation is located or what is causing it. Additional tests are needed to find the cause and location of the inflammation, suggests WebMD.