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What's the Usefulness of CRP Testing?

Measuring C-reactive protein in the blood  may -- or may not -- indicate that a person is at risk for heart disease.

WebMD Feature

Reviewed By Brunilda Nazario

By now, most of us are well-versed in the rules for keeping heart disease at bay: eat healthily, exercise, don't smoke or gain too much weight, and keep blood pressure and cholesterol levels under control. And familiarity with terms like HDL and LDL cholesterol is so common as to make for standard cocktail party chitchat.

But there's a lesser-known, relatively new player in heart-disease risk assessment called CRP, or C-reactive protein. A study in the January 2004 issue of The New England Journal of Medicine suggested that elevated levels of CRP could provide doctors with information that could ultimately prevent thousands of deaths from heart disease. But many reports have said that knowing CRP levels provides no clinical benefit whatsoever, making the whole subject a source of controversy.

The blood test for CRP indicates inflammation, which studies have shown to be critical in the development of atherosclerosis, or plaque build-up in the blood vessel walls.

According to the American Heart Association and the CDC, a CRP level of less than 1 mg per liter indicates a low risk of cardiovascular disease; 1-3 mg/L indicates moderate risk, and greater than 3 mg/L equals high risk.

But while the test itself is simple, its implications can be confusing.