At a Glance
Why Get Tested?
To screen for risk of developing heart disease
When to Get Tested?
Adults should be tested once every five years, or more frequently if being treated for high cholesterol or have one or more risk factors for heart disease. Children, teens, and young adults should be tested once between the ages of 9 and 11 and then again between the ages of 17 and 21.
A blood sample drawn from a vein in your arm or a fingerstick
Test Preparation Needed?
If you are having this test performed as part of the lipid profile, typically you will need to fast for 9-12 hours before the sample is collected; only water is permitted. Follow any instructions you are given.
The Test Sample
What is being tested?
Cholesterol is a substance (a steroid) that is essential for life. It forms the membranes for cells in all organs and tissues in the body. It is used to make hormones that are essential for development, growth, and reproduction. It forms bile acids that are needed to absorb nutrients from food.
A small amount of cholesterol circulates in the blood in complex particles called lipoproteins. Each particle contains a combination of protein, cholesterol, triglyceride, and phospholipid molecules and the particles are classified by their density into high-density lipoproteins (HDL), low-density lipoproteins (LDL), and very low-density lipoproteins (VLDL). HDL-C particles, sometimes called good cholesterol, carry excess cholesterol away for disposal and LDL-C particles, or bad cholesterol, deposit cholesterol in tissues and organs. The test for cholesterol measures total cholesterol (good and bad) that is carried in the blood by lipoproteins.
Monitoring and maintaining healthy levels of cholesterol is important for staying healthy. The body produces the cholesterol needed to work properly, but the source for some cholesterol is diet. If an individual has an inherited predisposition for high cholesterol levels or if he or she eats too much of the foods that are high in cholesterol, saturated fats, and trans unsaturated fats (trans fats), then the level of cholesterol in that person's blood may increase and have a negative impact on the person's health. The extra cholesterol in the blood may be deposited in plaques on the walls of blood vessels. Plaques can narrow or eventually block the opening of blood vessels, leading to hardening of the arteries (atherosclerosis) and increased risk of numerous health problems, including heart disease and stroke.
How is the sample collected for testing?
Most often, a blood sample is collected from a vein in the arm. Sometimes cholesterol is measured using a drop of blood collected by puncturing the skin on a finger. A fingerstick sample is typically used when cholesterol is being measured on a portable testing device, for example, at a health fair.
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?
If a cholesterol test is to be performed alone, it is not necessary to fast. However, if it is to be performed as part of a lipid profile, as it often is, then fasting for 9-12 hours before the test typically will be required; only water is permitted. Follow any instructions you are given.
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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
Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Sep 2002. PDF available for download at http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3full.pdf through http://www.nhlbi.nih.gov. Accessed July 21, 2013.
(©2012) American Heart Association. Cholesterol Levels. Available online at http://www.heart.org/HEARTORG/Conditions/Cholesterol/Cholesterol_UCM_001089_SubHomePage.jsp through http://www.heart.org. Accessed July 21, 2013.
(November 2012) American Association of Family Physicians. High Cholesterol. Available online at http://familydoctor.org/familydoctor/en/diseases-conditions/high-cholesterol.html through http://familydoctor.org. Accessed July 19, 2013.
Kavey R-EW, et al. Expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents: Summary report. Pediatrics 2011; 128: DOI:10.1542/peds.2009-2107C. PDF available for download at http://pediatrics.aappublications.org/site/misc/2009-2107.pdf through http://pediatrics.aappublications.org. Accessed July 19, 2013.
KidsHealth.org. Cholesterol and Your Child. Available online at http://kidshealth.org/parent/medical/heart/cholesterol.html# through http://kidshealth.org. Accessed July 20, 2013.
Kathiresan, S. 2006. Increased Small Low-Density Lipoprotein Particle Number, A Prominent Feature of the Metabolic Syndrome in the Framingham Heart Study. Circulation. PDF available for download at http://circ.ahajournals.org/content/113/1/20.full.pdf through http://circ.ahajournals.org. Accessed July 20, 2013.
Blake G, et al. September 23, 2002. Low-Density Lipoprotein Particle Concentration and Size as Determined by Nuclear Magnetic Resonance Spectroscopy as Predictors of Cardiovascular Disease in Women. Circulation. Available online at http://circ.ahajournals.org/content/106/15/1930.full through http://circ.ahajournals.org. Accessed July 20, 2013.
Blakenstein R, et al. July 2011. Predictors of Coronary Heart Disease Events Among Asymptomatic Persons With Low Low-Density Lipoprotein Cholesterol. Journal of the American College of Cardiology Volume 58, Issue 4, Pp 364–374.
Krauss R. 2010 Aug;21. Lipoprotein subfractions and cardiovascular disease risk. Curr Opin Lipidol (4):305-11. Abstract available online at http://www.ncbi.nlm.nih.gov/pubmed/20531184 through http://www.ncbi.nlm.nih.gov. Accessed July 2013.
Prado K, et al. 2011 Sep-Oct. Low-density lipoprotein particle number predicts coronary artery calcification in asymptomatic adults at intermediate risk of cardiovascular disease. J Clin Lipidol (5):408-13. Abstract available online at http://www.ncbi.nlm.nih.gov/pubmed/21981843 through http://www.ncbi.nlm.nih.gov. Accessed July 2013.
Lavie C, et.al. May 2012. To B or Not to B: Is Non–High-Density Lipoprotein Cholesterol an Adequate Surrogate for Apolipoprotein B? Mayo Clin Proc. 2010 May; 85(5): 446–450. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861974/ through http://www.ncbi.nlm.nih.gov. Accessed July 2013.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
National Heart, Lung, and Blood Institute of the National Institutes of Health, United States Department of Health and Human Services. Third report of the National Cholesterol Education Program (NCEP) Expert Panel on detection, evaluation, and treatment of high blood pressure in adults (Adult Treatment Panel III). Bethesda, Md. 2001 May. Available online at http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3_rpt.htm
American Heart Association. How to Get Your Cholesterol Tested. (Updated April 4, 2008) Available online at http://americanheart.org/presenter.jhtml?identifier=541 through http://americanheart.org. Accessed July 2008.
Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). May 2001. PDF available for download at http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3full.pdf through http://www.nhlbi.nih.gov. Accessed July 2008.
American Academy of Family Physicians. Cholesterol: What Your Level Means. (Updated October 2007). Available online at http://familydoctor.org/online/famdocen/home/common/heartdisease/risk/029.html through http://familydoctor.org. Accessed July 2008.
Daniels, SR, Greer FR, and the Committee on Nutrition. Lipid screening and cardiovascular health in childhood (clinical report). Jul 2008. Pediatrics 122:198-208.
American Academy of Pediatrics. AAP issues new guidelines on cholesterol screening (press release). 7 Jul 2008. Available online at http://www.aap.org/new/july08lipidscreening.htm through http://www.aap.org. Accessed August 2008.
American Academy of Pediatrics Lipid Screening and Cardiovascular Health in Childhood. Pediatrics Vol. 122 No. 1 July 2008, pp. 198-208. Available online at http://aappolicy.aappublications.org/cgi/content/full/pediatrics;122/1/198 through http://aappolicy.aappublications.org. Accessed September 2008.