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C Reactive Protein High Sensitivity

Cardiovascular disease (CVD) is the most common cause of death among adults in the United States. CVD includes comprises diseases of the heart and vascular system, including atherosclerosis, cerebrovascular disease, and peripheral artery disease.Early detection using screening tests could allow individuals to modify lifestyle risk factors and decrease the incidence of disease.

Several traditional risk factors are associated with higher risk for CVD events, including older age, male sex, high blood pressure, current smoking, abnormal cholesterol levels, diabetes, obesity, and physical inactivity. Risk factors can be combined to classify a person’s risk for a CVD event as low, intermediate, or high. Clinical calculators, such as the Framingham Risk Score and the Pooled Cohort Equations, are available to quantify a person’s 10-year CVD event risk.

Current evidence indicates that inflammation plays a central role in the pathogenesis of atherosclerosis and thrombosis and that hsCRP is a marker of low-grade vascular inflammation that is predictive of future cardiovascular events. For this reason, anumber of clinical guidelines, including those from the American College of Cardiology and the American Heart Association, recommend considering the measurement of hsCRP level to clarify treatment decisions for patients whose risk assessment is borderline or unclear using these models. The American Association of Clinical Endocrinologists’ 2017 guidelines include hsCRP level, as part of the Reynolds Risk Score, as a possible CVD risk assessment tool to stratify borderline cases.

High-sensitivity C-reactive protein is a serum protein involved in inflammatory and immune responses. A threshold of greater than 2 or 3 mg/L is used in clinical practice to signify increased cardiovascular risk. The US Preventive Services Task Force (USPSTF) reviewed the evidence for using high sensitivity C-reactive protein (hsCRP) to screen for cardiovascular disease.

In 2018, USPSTF reviewed evidence of whether hsCRP measurement improves calibration, discrimination, or risk reclassification when added to CVD risk assessment using traditional risk factors. Calibration measures the agreement between observed and predicted outcomes, discrimination measures the ability to distinguish between persons who will and will not have an event, and reclassification measures the ability to correctly reassign persons into clinically meaningful risk strata.

USPSTF reviewed 25 articles representing 49 cohorts for hsCRP level. Evidence for adding hsCRP was inconsistent, showing at most a small improvement in discrimination In the only study that added hsCRP to the Pooled Cohort Equations (MESA), hsCRP level did not improve discrimination.

Testing for hsCRP is noninvasive, and there is little direct harm from the tests, but abnormal test results may lead to further testing, procedures, and lifelong medication use. Psychological harms may result from reclassification into a higher-risk category for CVD events.

USPSTF concluded that current evidence is insufficient to assess the balance of benefits and harms of adding hsCRP to traditional risk assessment for CVD in asymptomatic adults to prevent CVD events.

Specimen requirement is a minimum of 0.5 mL of serum (one SST tube). Gross lipemia or hemolysis interferes with this test.


Risk Assessment for Cardiovascular Disease With Nontraditional Risk Factors: US Preventive Services Task Force Recommendation Statement. JAMA. Published online July 10, 2018. doi:10.1001/jama.2018.8359

Buckley DI, Fu R, Freeman M, Rogers K, Helfand M. C-reactive protein as a risk factor for coronary heart disease: a systematic review and meta-analyses for the U.S. Preventive Services Task Force. Ann Intern Med. 2009;151(7):483-495.

Ridker PM, Danielson E, Fonseca FA, et al; JUPITER Study Group. Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein.N Engl J Med. 2008;359(21):2195-2207.

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