By David T. Moran, MD A cholesterol test measures the total amount of cholesterol in the blood. It is generally done along with blood tests that measure a person's HDL , also known as the good carrier for cholesterol and LDL , or the so-called bad carrier for cholesterol.
Cholesterol is a waxy substance that is used for many body processes.
A cholesterol test may be ordered to evaluate a person's risk for various conditions. Adults 20 years or over should be tested every five years for cholesterol, LDL, HDL, and triglycerides. A cholesterol test may also be ordered to evaluate disorders of the kidney, liver, or thyroid gland. A blood sample needs to be taken in order to measure the level of blood cholesterol. The blood is usually drawn from a vein in the forearm or the hand.