C-reactive protein is a substance found in the blood of human beings and other animals. The protein, often called CRP, plays an important role in inflammation, the redness, swelling, and heat with which the body responds to injury or infection. Inflammation, together with the disease-fighting process known as the immune response, is how the body recognizes and removes infectious agents or damaged tissues, and begins healing.
Medical researchers are interested in CRP because high levels are associated with increased risk of heart attacks and strokes. Scientists believe that cholesterol deposits called plaques within the arteries will more likely rupture when CRP levels are high. When plaques rupture, blood clots form inside the arteries. A clot can block arteries of the heart, causing heart attack, or arteries to the brain, causing stroke. High levels of CRP are also a risk factor for type 2 diabetes, a disease in which blood sugar levels are abnormal. Many patients with diabetes also have heart disease. CRP levels are high in many patients with arthritis and other disorders that result from inappropriate or uncontrolled inflammation.
Physicians recommend regular exercise, not smoking, and a healthy diet to prevent heart disease, stroke, and diabetes. All these activities also reduce CRP levels. Certain drugs, such as statins, that lower heart attack risk also lower CRP levels. CRP can be measured by a blood test. A CRP level less than 1.0 milligram per liter of blood is considered desirable. A level greater than 3 milligrams per liter is considered high.
See also Cholesterol; Diabetes; Heart (Coronary artery disease); Inflammation; Stroke (Causes).
