What is being tested?

Cholesterol is a substance that is essential for life. It helps form the membranes for cells in all organs and tissues in your 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 your body’s cholesterol circulates in the blood in complex particles called lipoproteins. These lipoproteins include some particles that carry excess cholesterol away for disposal (see HDL, good cholesterol) and some particles that deposit cholesterol in tissues and organs (see LDL, bad cholesterol). The test for cholesterol measures all cholesterol (good and bad) that is carried in the blood by lipoproteins. Cholesterol comes from your diet, and is also made in your liver.

Your body produces the necessary quantity of cholesterol for your body to work properly but some cholesterol is also provided by your diet. If you have inherited a high cholesterol levels or if you eat too much of the foods which are high in cholesterol or saturated fats then levels of cholesterol in your blood may increase and have a bad effect on your health. The extra cholesterol in your blood may be deposited on the walls of the blood vessels. The cholesterol is deposited as plaques and can narrow and eventually block the opening of blood vessels leading to hardening of the arteries (atherosclerosis) and and increased risk of heart disease and stroke.

How is the sample collected for testing?
Blood sample is usually collected from a vein in your arm. Sometimes cholesterol is measured using a drop of blood collected by puncturing the skin on a finger. A finger sample is typically used when cholesterol is being measured on a portable testing device. A high reading should always be confirmed by testing a blood sample taken from a vein in your arm.