Cholesterol test

Blood test

Cholesterol producers

Definition

A cholesterol test measures the amount of cholesterol and triglycerides in serum (part of the blood).

Alternative Names

Total cholesterol; Lipid test; Lipoprotein test; Lipid profile

How the test is performed

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins to fill with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation and prevent bruising. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

Note that veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

How to prepare for the test

To get accurate results, you should fast for 9 to 12 hours before the test. The health care provider may advise you to stop taking drugs that can affect the test. (See "Special considerations.") You may drink water during the fast, but other beverages such as coffee, tea, or soda may affect results.

For infants and children:

The preparation you can provide for this test depends on your child's age and previous experiences. For specific information regarding how you can prepare your child, see the following topics: