Should You Have the CRP Test?

Posted: Feb. 1, 2005

The high sensitivity C-reactive protein (hs-CRP) test takes the traditional cardiac check-up a step further, pinpointing those people who are at a much higher risk than others for heart disease.

The test entails a simple, inexpensive blood test. From hs-CRP results, doctors gain crucial insight into inflammation of the blood vessels around the heart.

How C-reactive protein relates to heart disease
The body produces C-reactive protein (CRP) during the general process of inflammation. When atherosclerosis damages arteries around the heart, they become inflamed, which triggers CRP production.

Who needs the test?
A panel of experts convened by the American Heart Association and the Centers for Disease Control and Prevention has recommended limited use of the test. The group saw no need for hs-CRP screening of the entire adult population as a public health measure.

Hs-CRP can, however, be an independent marker of risk and may be useful as a discretionary tool for evaluating people with moderate risk. The test might be useful when a physician is undecided about a course of treatment for a patient who is considered intermediate risk.

The panel noted that these recommendations are based on current evidence, and may need to be changed as new clinical trial results become available.

How do doctors test for CRP?
Physicians measure CRP with a simple blood test that does not require fasting. General CRP blood testing has been around for years, but only one kind, the high sensitivity C-reactive protein (hs-CRP) test, helps determine heart disease risk.

With hs-CRP test results, a level above three raises major concern because it means a person’s risk for heart attack is at least doubled. One to three merits some concern, but is not serious. Readings of 10 and above are generally attributed to an infection somewhere in the body, not arterial inflammation.

Comparing hs-CRP, cholesterol and stress tests
The exercise stress test reveals when narrowed arteries cause a shortage of blood going to the heart. It is still a vital heart disease risk indicator.

LDL cholesterol is important to watch because it can narrow and clog arteries. There are two types of LDL cholesterol, the bad kind and the really bad kind, called oxidized LDL cholesterol.

The available cholesterol test does not differentiate between these two types; it only tells a person’s total LDL level. However, this bad, oxidized type, which hurts the arteries and speeds up plaque formation, has a direct correlation to CRP levels. Arteries can produce CRP directly at sites where there is cholesterol buildup. So, hs-CRP testing offers a window into how much of the especially bad cholesterol a person has in his or her blood.

Is arterial inflammation the only cause of high CRP?
Inflammation in the body due to infection or a serious arthritic flare can raise CRP. Before getting an hs-CRP test, patients should tell their doctors if they are experiencing health problems that can cause general inflammation, for example, joint problems or a respiratory infection.

Source: Cleveland Clinic news release

We Have Answers Do you have medical questions or need help finding a doctor? The experts at Columbia St. Mary's and Advanced Healthcare can help. Click here.