C-reactive protein: A plasma protein that rises in the blood with the inflammation from certain conditions.
C-reactive protein (CRP) is one of the plasma proteins known as acute- phase proteins: proteins whose plasma concentrations increase (or decrease) by 25% or more during inflammatory disorders.
CRP can rise as high as 1000-fold with inflammation. Conditions that commonly lead to marked changes in CRP include infection, trauma, surgery, burns, inflammatory conditions, and advanced cancer. Moderate changes occur after strenuous exercise, heatstroke, and childbirth. Small changes occur after psychological stress and in several psychiatric illnesses.
CRP is therefore a test of value in medicine, reflecting the presence and intensity of inflammation, although an elevation in C-reactive protein is not the telltale diagnostic sign of any one condition.
Since inflammation is believed to play a major role in the development of coronary artery disease, markers of inflammation have been tested in respect to heart health. CRP was found to be the only marker of inflammation that independently predicts the risk of a heart attack. (N Engl J Med 2000;342:836-43.) The CRP test may therefore be added to the screening battery of cholesterol and other lipid tests to detect people at risk for a heart attack.