Also Known As
hsCRP
High-sensitivity CRP
Ultra-sensitive CRP
Cardiac CRP
CRP for heart disease
Formal Name
High-sensitivity C-reactive Protein
This article was last reviewed on
This article waslast modified on November 5, 2017.
At a Glance
Why Get Tested?

To help assess your risk of developing cardiovascular disease

When To Get Tested?

No current consensus exists on when to get tested; hs-CRP is often ordered in conjunction with other tests that are performed to assess risk of heart disease, such as a lipid profile (cholesterol, triglycerides, HDL-C, LDL-C) when your healthcare provider would like additional information on your risk.

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

You may be instructed to fast for 9-12 hours before the blood sample is taken if a lipid profile also is going to be done at the same time. You should be healthy at the time of the sample collection, without any recent illnesses, infections, inflammation, or injuries.

You may be able to find your test results on your laboratory's website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab's website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab's website or portal, or contact your healthcare practitioner in order to obtain your test results.

Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called "normal" values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

For more information, please read the article Reference Ranges and What They Mean.

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.

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.

See More
See Less
Common Questions
  • How is it used?

    A high-sensitivity C-reactive protein (hs-CRP) test may be used to help evaluate an individual for risk of cardiovascular disease (CVD). It may be used in combination with a lipid profile or with other cardiac risk markers, such as a lipoprotein-associated phospholipase A2 (Lp-PLA2) test, to provide added information about heart disease risk.

    CRP is a protein that increases in the blood with inflammation. Studies have suggested 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. The hs-CRP test accurately measures low levels of C-reactive protein to identify low but persistent levels of inflammation and thus helps predict a person's risk of developing CVD.

    High-sensitivity CRP is thought by some experts to be a useful test for determining risk of CVD, heart attacks, and strokes and that hs-CRP can play a role in the evaluation process before a person develops one of these health problems. Some say that the best way to predict risk is to combine a good marker for inflammation, like hs-CRP, with the lipid profile. Several groups have recommended that this test be used for people who have a moderate risk of heart attack over the next 10 years.

    However, not all health professionals agree on hs-CRP's usefulness. Clinical trials that involve measuring hs-CRP levels are currently underway in an effort to better understand its role in cardiovascular events. These studies will help to form and refine guidelines on its use in screening and treatment decisions.

  • When is it ordered?

    Currently, there is no consensus on when to get tested, though some guidelines include recommendations on hs-CRP testing. For example, a guideline from the American College of Cardiology Foundations and the American Heart Association says that hs-CRP testing may be useful when men 50 years old or younger and women 60 years old or younger have intermediate risk. It also may be useful for treatment decisions when men and women are older than these respective ages and have LDL-C less than 130 mg/L and meet several other criteria, such as no existing heart disease, diabetes, kidney disease, or inflammatory conditions.

    When hs-CRP is evaluated, it may be repeated to confirm that a person has persistent low levels of inflammation.

  • What does the test result mean?

    Relatively high levels of hs-CRP in otherwise healthy individuals have been found to be predictive of an increased risk of a future heart attack, stroke, sudden cardiac death, and/or peripheral arterial disease, even when cholesterol levels are within an acceptable range.

    People with higher hs-CRP values have the highest risk of cardiovascular disease and those with lower values have less risk. Specifically, individuals who have hs-CRP results at the high end of the normal range have 1.5 to 4 times the risk of having a heart attack as those with hs-CRP values at the low end of the normal range.

    The American Heart Association and U.S. Centers for Disease Control and Prevention have defined risk groups as follows:

    • Low risk: less than 1.0 mg/L
    • Average risk: 1.0 to 3.0 mg/L
    • High risk: above 3.0 mg/L

    These values are only a part of the total evaluation process for cardiovascular diseases. Additional risk factors to be considered are elevated levels of cholesterol, LDL-C, triglycerides, and glucose. In addition, smoking, high blood pressure (hypertension), and diabetes also increase the risk level.

  • Is there anything else I should know?

    Taking nonsteroidal anti-inflammatory drugs (NSAIDs, e.g., aspirin, ibuprofen, and naproxen) or statins may reduce CRP levels in blood. Both anti-inflammatory drugs and statins may help to reduce inflammation, thus reducing CRP.

    It is important that any person having this test be in a healthy state for the results to be of value in predicting the risk of coronary disease or heart attack. Any recent illness, tissue injury, infection, or other general inflammation will raise the amount of CRP and give a falsely elevated estimate of risk.

    Women on hormone replacement therapy have been shown to have elevated hs-CRP levels.

    Since the hs-CRP and CRP tests measure the same protein, people with chronic inflammation, such as those with arthritis, should not have hs-CRP levels measured. Their CRP levels will already be very high due to the arthritis, so results of the hs-CRP test will not be meaningful.

  • Is hs-CRP specific for predicting heart disease?

    No. CRP is a marker of inflammation, a process that can affect a number of organ systems. Most studies to date have focused on heart disease, but new research shows that having CRP in the high normal range may also be associated with other diseases such as colon cancer, complications of diabetes, and obesity.

  • I have had cholesterol tests but never an hs-CRP test. Why?

    You may not fall into one of the categories for which the test is currently recommended. Also, experts still don't agree on when and how often the hs-CRP test should be ordered. As more clinical studies are completed that support its utility, this test may be more frequently ordered.

  • What is the difference between regular CRP and hs-CRP tests?

    Both tests measure the same protein in the blood. The hs-CRP test is for apparently healthy people to determine their risk of cardiovascular disease. It measures CRP in the range from 0.5 to 10 mg/L. The CRP test is ordered to evaluate people who have signs and symptoms of a serious bacterial infection or of a serious chronic inflammatory disease such as rheumatoid arthritis. It measures CRP in the range from 10 to 1000 mg/L.

See More Common Questions See Less Common Questions
View Sources

Sources Used in Current Review

Lutsep, H. and Stetka, B. (2015 January 16). New Stroke Prevention Guidelines: A Quick and Easy Guide. Medscape Neurology [On-line information]. Available online at http://www.medscape.com/viewarticle/838140 through http://www.medscape.com. Accessed February 2015.

Delgado, J. et. al. (2014 November). Cardiovascular Disease (Non-traditional Risk Markers) - Risk Markers - CVD (Non-traditional). ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/CVDRiskMarkerNontrad.html?client_ID=LTD through http://www.arupconsult.com. Accessed February 2015.

Yousuf, O. et. al. (2013). High-Sensitivity C-Reactive Protein and Cardiovascular Disease, A Resolute Belief or an Elusive Link? Medscape Multispecialty from J Am Coll Cardiol. 2013;62(5):397-408 [On-line information]. Available online at http://www.medscape.com/viewarticle/808448 through http://www.medscape.com. Accessed February 2015.

(2014 August 4). Who Is at Risk for Atherosclerosis? National Heart Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/health/health-topics/topics/atherosclerosis/atrisk through http://www.nhlbi.nih.gov. Accessed February 2015.

Teitel, A. (Updated 2013 February 11). C-reactive protein. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003356.htm through http://www.nlm.nih.gov. Accessed February 2015.

Whelton, S. et. al. (2013). Elevated High-sensitivity C-reactive Protein as a Risk Marker of the Attenuated Relationship Between Serum Cholesterol and Cardiovascular Events at Older Age, The ARIC Study. Medscape Multispecialty from Am J Epidemiol. 2013;178(7):1076-1084 [On-line information]. Available online at http://www.medscape.com/viewarticle/811811 through http://www.medscape.com. Accessed February 2015.

Pagana, K. D., Pagana, T. J., and Pagana, T. N. (© 2015). Mosby's Diagnostic & Laboratory Test Reference 12th Edition: Mosby, Inc., Saint Louis, MO. Pp 306-307.

(March 1, 2012) Assessing Cardiovascular Risk: Guideline Synthesis. Agency for Healthcare Research and Quality (AHRQ). Available online at http://www.medscape.com/viewarticle/759314_4 through http://www.medscape.com. Accessed March 4, 2015.

Sources Used in Previous Reviews

American College of Cardiology clinical trials pages. Available online at http://www.acc.org/education/online/trials/acc2001/prince.htm through http://www.acc.org.

Santa Fe Colloquium on Preventive Cardiovascular Therapy. Available online at http://www.acc.org/education/online/sante%5Ffe/ridker.htm through http://www.acc.org.

Ridker PM, Stampfer MJ, Rifai N. Novel risk factors for atherosclerosis: a comparison of C-reactive protein, fibrinogen, homocysteine, lipoprotein(a), and standard cholesterol screening as predictors of peripheral arterial disease. JAMA 2001; 285:2481-2485. (May 16, 2001).

Ridker PM, Hennekens CH, Buring JE, and Rifai N. C-reactive protein and other markers of inflammation in the prediction of cardiovascular disease in women. NEJM 2000; 342:836-843. (March 23, 2000).

ARUP Lab fact sheet. Available online at http://www.aruplab.com/guides/clt through http://www.aruplab.com.

American Heart Association Journal Report 01/28/2003. AHA/CDC panel issues recommendations on CRP testing. Available online at http://www.americanheart.org/presenter.jhtml?identifier=3007984 through http://www.americanheart.org.

MedlinePlus Medical Encyclopedia. C-reactive protein. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003356.htm. Accessed December 2008.

The Evolving Role of High-Sensitivity C-Reactive Protein in Cardiovascular Health: An Expert Interview With Paul M. Ridker, MD. Posted 01/03/2006. Available online at http://www.medscape.com/viewarticle/519642 through http://www.medscape.com. Accessed December 2008.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 319-321.

(© 1995-2012). Test ID: HSCRP C-Reactive Protein, High Sensitivity, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/82047 through http://www.mayomedicallaboratories.com. Accessed May 2012.

Devaraj, S. and Lin, J. (Updated 2012 February 24). High-Sensitivity C-Reactive Protein. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2094831-overview#showall through http://emedicine.medscape.com. Accessed May 2012.

Delgado, J. et. al. (Updated 2011 April). Cardiovascular Disease (Non-traditional Risk Markers) - Risk Markers - CVD (Non-traditional). ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/CVDRiskMarkerNontrad.html?client_ID=LTD through http://www.arupconsult.com. Accessed May 2012.

Davidson, M. (2011 May 19). hs-CRP: What Is Proven and Unproven? Medscape Today from Circulation. 2011;123:731-738 [On-line information]. Available online at http://www.medscape.com/viewarticle/742591 through http://www.medscape.com. Accessed May 2012.

Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pg 239.

Greenland P, et al. 2010 ACCF/AHA Guideline for Assessment of Cardiovascular Risk in Asymptomatic Adults: Executive Summary, A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Available online at http://circ.ahajournals.org/content/122/25/2748.full#sec-20 through http://circ.ahajournals.org. Accessed May 2012.

See More
See Less

Ask a Laboratory Scientist

 

Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, the American Society for Clinical Laboratory Science (ASCLS). Click on the Contact a Scientist button below to be re-directed to the ASCLS site to complete a request form. If your question relates to this web site and not to a specific lab test, please submit it via our Contact Us page instead. Thank you.

Contact a Scientist