C-reactive protein (CRP) is a very sensitive acute phase reactant. Acute phase reactants are a class of proteins that increase during general inflammation. They are usually nonspecific markers of inflammation. There are many acute phase reactants and there are negative acute phase reactants (serum proteins that decrease during inflammation). One important acute phase protein associated with cardiovascular health is CRP. Serum CRP levels increase following a variety of pro-inflammatory events such as infection, tissue necrosis, trauma, surgery and even malignancy. CRP levels can increase quickly and dramatically (often 100 fold) during inflammation. CRP can activate complement, bind Fc receptors and can function as an opsonin, enhancing phagocytosis in certain infections. Measurement of CRP is not new, it has been on clinical laboratory testing menus for decades. However, a newer version of the CRP test is now in use to assess cardiovascular risk.
High sensitivity-CRP (hs-CRP) assays have been developed that are more sensitive to subtle changes that can occur during chronic vascular inflammation. (Recall that atherosclerosis is an inflammatory process). By measuring hsCRP we can get a glimpse at vascular function. hs-CRP has been shown to be an independent risk factor for atherosclerotic disease and cardiac death. A 2002 prospective study of more than 27,000 patients showed that hs-CRP concentration is a stronger predictor of cardiovascular events than the LDL-cholesterol level.