Cholesterol is a substance that is similar to fat. Cells need cholesterol. There are many types of cholesterol. When there is too much or too little of one type, problems can develop.
Cholesterol tests measure the levels of cholesterol in the blood. Different components of cholesterol can be measured:
- Total cholesterol
- HDL-cholesterol—the "good" cholesterol
- LDL-cholesterol—the "bad" cholesterol
- Lipoprotein profile—measures all the above
Plaque Formation in Blood Vessel—Side Effect of High HDL Cholesterol
Reasons for Test
The levels of cholesterol in your blood play an important role in determining your risk of cardiovascular disease (CVD), which can lead to heart attacks and strokes. For example:
- High LDL levels increase the risk of CVD.
- Low HDL levels increase the risk of CVD.
- High triglyceride levels increase the risk of CVD.
What to Expect
Prior to Test
Steps to take before the test depend on the test you are having. For example:
- Lipoprotein profile—You will need to not eat or drink for 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 roll up your sleeve. An elastic band will be wrapped around your upper arm. An area on your arm will be cleaned with alcohol. The needle will then be inserted into your arm vein. A small amount of blood will be drawn into a tube. The needle will be removed. Pressure will be applied to the puncture site. A small bandage may be placed on the site. Your blood will be sent to a lab for testing.
You will be able to leave after the test is done. When you arrive home:
- Go back to your regular diet.
- If told to do so by your doctor, take your medicines as usual.
- If you have an area of bruising, apply pressure to the area. Use a piece of cotton under the bandage.
How Long Will It Take?
A few minutes
Will It Hurt?
It may hurt slightly when the needle is inserted.
American Heart Association
National Heart, Lung, and Blood Institute
Alberta Health and Wellness
Heart and Stroke Foundation of Canada
Akosah KO, Schaper A, Cogbill C, Schoenfeld P. 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.
Illustrated Guide to Diagnostic Tests. Springhouse, PA: Springhouse Corporation; 2001.
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/dci/Diseases/Hbc/HBC_WhatIs.html. Updated September 2008. Accessed January 26, 2008.
Last reviewed October 2009 by ]]>Brian P. Randall, MD]]>
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