Cholesterol is a waxy substance that is similar to fat. There are different types of cholesterol including:
- High-density lipoprotein (HDL) cholesterol
- Low-density lipoprotein (LDL) cholesterol
Cholesterol tests measure the levels of cholesterol in the blood. They can measure the amount of HDL cholesterol, LDL cholesterol, and your total cholesterol levels. A test called the lipid profile test may be used. This test measures the cholesterol levels plus triglycerides. Triglycerides are a type of fat or lipid in the blood.
Reasons for Test
This test is done to measure the levels of cholesterol in the blood. Abnormal levels of cholesterol are linked to an increased risk of plaque formation in blood vessels. This plaque formation can lead to heart attacks or strokes. The results will be used to estimate your risk of heart disease. For example:
- High LDL levels increase the risk of heart disease.
- Low HDL levels increase the risk of heart disease.
Plaque Formation in Blood Vessel—Side Effect of High LDL Cholesterol
There are no major complications associated with this test.
What to Expect
Prior to Test
Steps to take before the test depend on the test you are having. For example:
- Fasting lipid profile—You will need to stop eating or drinking 9-12 hours before the test. Water is allowed during this time.
- Total cholesterol test and total cholesterol test with HDL measurement—You do not need to fast.
Description of Test
You will be asked to sit. An area inside your elbow will be cleaned with an antiseptic wipe. A large band will be tied around your arm. The needle will then be inserted into a vein. A tube will collect the blood from the needle. The band on your arm will be removed. Once all the blood is collected, the needle will be removed. Some gauze will be placed over the site to help stop bleeding. You may also be given a bandage to place over the site. The process takes about 5-10 minutes.
After the blood sample is collected, you may need to stay seated for 10-15 minutes. If you are lightheaded, you may need to stay seated longer. When you feel better, you can leave.
In some cases, a bit of blood may ooze from the vein beneath the skin and cause a bruise. The risk of bruising can be minimized by placing firm pressure over the puncture site. A bruise will usually resolve in a day or two.
Call Your Doctor
Call your doctor if any of the following occurs:
- You have increased redness, pain, or discharge from the blood test site.
- You have severe bruising or swelling.
In case of an emergency, call for emergency medical services right away.
American Heart Association
National Heart, Lung, and Blood Institute
Canadian Cardiovascular Society
Heart and Stroke Foundation of Canada
Akosah KO, Schaper A, et al. Preventing myocardial infarction in the young adult in the first place: how do the National Cholesterol Education Panel III guidelines perform? J Am Coll Cardiol. 2003;41:1475-1479.
Cholesterol. Lab Tests Online—American Association for Clinical Chemistry website. Available at: http://labtestsonline.org/understanding/analytes/cholesterol/tab/test. Updated December 29, 2014. Accessed January 26, 2015.
How to get your cholesterol tested. American Heart Association website. Available at: http://www.heart.org/HEARTORG/Conditions/Cholesterol/SymptomsDiagnosisMonitoringofHighCholesterol/How-To-Get-Your-Cholesterol-Tested_UCM_305595_Article.jsp. Updated August 5, 2014. Accessed January 26, 2015.
Law MR, Wald NJ. Risk factor thresholds: their existence under scrutiny. Br Med J . 2002;324:1570-1576.
What is cholesterol? National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/hbc/. Updated September 19, 2012. Accessed January 26, 2015.
Last reviewed January 2015 by Marcin Chwistek, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.