C-reactive protein: An acute-phase plasma protein whose blood concentration reflects the presence and intensity of inflammation. Abbreviated CRP. Conditions that commonly lead to marked increases 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. Elevated levels of CRP are associated with atherosclerosis and heart disease.