Additional Information

Blood levels of C-Reactive Protein (CRP) are known to rise rapidly from normal baseline levels of often <3 mg/L to as high as 500 mg/L as part of the body’s nonspecific inflammatory response to infection or injury.  In more recent years, the utility of measuring CRP has expanded from its historical use as a sensitive marker of acute inflammation to include assessment of cardiac events and risk. A prognostic value for measuring CRP has been suggested from studies with cardiac patients where elevated levels of CRP were associated with a higher risk of having a future cardiac event. Elevated levels of CRP have been associated with poor prognosis in cases of stable angina, unstable angina and myocardial infarction. Cardiac disease is believed to be the end result of an interplay between minor changes in the cardiovascular endothelium and the corresponding inflammatory response to these changes. The ability to measure CRP at extremely low concentrations has raised the possibility of using CRP to detect early inflammatory responses and potentially detect cardiac disease in the preclinical stages.  Recent evidence supporting this potential application has shown that high baseline values of CRP in individuals without a history of cardiac disease were associated with an increased incidence of subsequent cardiac events.  It is important to note that baseline CRP values are known to be influenced by various factors (elevated blood pressure, obesity, hormone replacement therapy, metabolic syndrome/diabetes, low HDL/high triglycerides, chronic infections, smoking) and a single measurement may lead to an erroneous assessment of early cardiac inflammation. Increases in CRP levels are nonspecific and should not be interpreted without a complete clinical history. It is recommended, therefore, that any estimations of inflammation be based on changes in CRP values from multiple measurements and be used in conjunction with the values of other cardiac risk indicators (i.e., HDL, cholesterol, etc.). 

In 2003, the American Heart Association (AHA) and Centers for Disease Control (CDC) issued a joint Scientific Statement recommending 2 hs-CRP levels be obtained, optimally 2 weeks apart, then averaged for cardiac risk assessment.