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Also known as: hsCRP; High-sensitivity CRP; Ultra-sensitive CRP; Cardiac CRP; CRP for heart disease
Formal name: High-sensitivity C-reactive Protein

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Were you looking for the CRP test, used to evaluate general inflammation?

The Test Sample

What is being tested?

C-reactive protein (CRP) is a protein that increases in the blood with inflammation and infection as well as following a heart attack, surgery, or trauma. Thus, it is one of several proteins that are often referred to as acute phase reactants. The high-sensitivity CRP test measures low levels of CRP in the blood to identify low levels of inflammation that are associated with risk of developing cardiovascular disease (CVD).

There are two different tests that measure CRP and each test measures a different range of CRP level in the blood for different purposes:

  • The standard CRP test measures markedly high levels of the protein to detect diseases that cause significant inflammation. It measures CRP in the range from 10 to 1000 mg/L.
  • The hs-CRP test accurately detects lower levels of the protein than the standard CRP test and is used to evaluate individuals for risk of CVD. It measures CRP in the range from 0.5 to 10 mg/L.

It is now believed that a persistent low level of inflammation plays a major role in atherosclerosis, the narrowing of blood vessels due to build-up of cholesterol and other lipids, which is often associated with CVD.

CVD causes more deaths in the U.S. each year than any other cause, according to the American Heart Association. A number of risk factors, such as family history, high cholesterol, high blood pressure, being overweight or diabetic, have been linked to the development of CVD, but a significant number of people who have few or no identified risk factors will also develop CVD. This fact has lead researchers to look for additional risk factors that might be either causing CVD or that could be used to determine lifestyle changes and/or treatments that could reduce a person's risk.

High-sensitivity CRP is one of a growing number of cardiac risk markers that are used to help determine a person's risk. Some studies have shown that measuring CRP with a highly sensitive assay can help identify the risk level for CVD in apparently healthy people. This more sensitive test can measure CRP levels that are within the higher end of the reference range. These normal but slightly high levels of CRP in otherwise healthy individuals can predict the future risk of a heart attack, stroke, sudden cardiac death, and peripheral arterial disease, even when cholesterol levels are within an acceptable range.

How is the sample collected for testing?

A blood sample is drawn by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed; however, fasting for 9-12 hours before the blood sample is taken may be required if a lipid profile (including triglycerides) is to be done at the same time. In addition, the person being tested should be healthy at the time of the sample collection, without any recent illnesses, infections, inflammation, or injuries.