High levels of C-reactive protein are caused by the inflammation that accompanies certain infections and serious diseases, says WebMD. The measurement determines the level of inflammation within the body, but tests do not indicate where the inflammation occurs.
A CRP test is used as a diagnostics tool to alert physicians that an infection or serious disease may be present, according to WebMD. Hours after surgery, CRP levels begin to climb but return to normal by the third day. Levels that stay consistent on or following the third day indicate a possible infection.
If an infection is not present, high levels of CRP let physicians know to perform additional tests to determine the cause of the inflammation, claims WebMD. Such causes include lymphoma, diseases that attack the immune system, giant cell arteritis or rheumatoid arthritis.
A CRP test may also be used to determine how well a patient is responding to certain treatments, according to WebMD. This is especially true for patients suffering from an infection or cancer as CRP levels typically climb immediately following treatment but begin to drop once the patient's body responds to treatment.
Although less popular than a regular CRP test, a high-sensitivity CRP test may determine a patient's risk of having a heart attack or stroke, says WebMD. The results indicate what course of action the patient must take to lower their risk.