Were you looking for the CRP test, used to evaluate general inflammation?
At a Glance
Why Get Tested?
To assess your risk of developing cardiovascular disease
When to Get Tested?
No current consensus exists on when to get tested; hs-CRP is most 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).
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.
The Test Sample
What is being tested?
C-reactive protein (CRP) is a protein produced by the liver and released into the bloodstream. The level of CRP in the blood increases with inflammation and infection as well as following a myocardial infarction (MI, heart attack), surgery, and trauma. Thus, it is one of several proteins that are often referred to as acute phase reactants. The high-sensitivity test measures small amounts of CRP in the blood in order to help evaluate a person's risk of developing cardiovascular disease (CVD).
There are two different tests that measure CRP: the standard CRP test and the high-sensitivity CRP (hs-CRP) test. Each measures different ranges of CRP levels in the blood for different purposes. The standard test measures markedly high levels of the protein to detect diseases causing significant inflammation. The hs-CRP test can more accurately detect lower concentrations of the protein than the standard CRP test and is used to evaluate individuals for risk of CVD.
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 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 of CVD.
High-sensitivity CRP is one of a growing number of cardiac risk markers that are used to help determine a person's risk of developing CVD. Studies have shown that measuring CRP with a highly sensitive assay can identify the risk level for CVD in apparently healthy people. This more sensitive test can measure CRP concentrations that are within the higher end of the normal range. These normal but relatively 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, you may be instructed to fast for 9-12 hours before the blood sample is taken if a lipid profile (including triglycerides) is to be done at the same time. In addition, you should be healthy at the time of the sample collection, without any recent illnesses, infections, inflammation, or other tissue injuries.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
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.
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.