What Is CRP?
It is not a new test, but it is a test in the news. CRP, also known as C-Reactive Protein, is a test which measures the concentration in blood serum of a special type of protein produced in the liver that is present during episodes of acute inflammation or infection. In the body, CRP plays the important role of interacting with the complement system, an immunologic defense mechanism.
As a blood test, CRP is not specific. A high result serves as a general indication of acute inflammation. In cases of inflammatory rheumatic diseases, such as rheumatoid arthritis and lupus, doctors can utilize the CRP test to assess the effectiveness of a specific arthritis treatment and monitor periods of disease flareup. It's value is as a general indicator, not specific.
Normally there is no CRP in blood serum. From Lab Tests Online, "a high or increasing amount of CRP in your blood suggests that you have an acute infection or inflammation. Although a result above 1 mg/dL is usually considered high for CRP, most infections and inflammations result in CRP levels above 10 mg/dL".
A positive CRP may be an indicator of several conditions, including:
A positive CRP also can be detected during the last half of pregnancy or with the use of oral contraception.
Another blood test often ordered in conjunction with CRP is known as ESR (erythrocyte sedimentation rate or sedrate). Both CRP and ESR give similar information about non-specific inflammation. CRP appears and disappears more quickly than changes in ESR. Therefore, your CRP level may drop to normal following successful treatment, whereas ESR may remain elevated for a longer period.
Most recently, CRP has made headlines as it relates to heart disease. New studies indicate CRP may be elevated in heart attacks. It is yet to be determined if CRP serves as a marker of heart disease or whether it plays a part in causing atherosclerotic disease (hardening of the arteries).
There is also a high sensitivity CRP test (hs-CRP) in addition to the regular CRP test. The hs-CRP measures very low amounts of CRP in the blood and is typically used to assess risk for heart problems.