Cholesterol test facts
- Cholesterol is a naturally occurring substance in the body that is an important part of normal body function.
- Cholesterol has two main types: HDL, or good cholesterol, that protects against heart disease, stroke and peripheral vascular disease; and LD, or bad, cholesterol, which increases the risk of these conditions.
- Cholesterol tests measure total cholesterol as well as HDL and LDL levels in the blood. Triglycerides, another type of fat present in the bloodstream, may also be measured.
- Cholesterol tests are usually ordered and blood drawn in a doctor's office. There are also home test kits available. It is important to be fasting for the tests to be accurate. Typically, a fasting test is performed first thing in the morning before the individual has eaten anything for the day. Fasting typically requires 12 hours without food. Water, plain tea or coffee are permitted, and hydration is required. No other liquids are acceptable during the fasting period. Patients cannot add sugar, artificial sweeteners, cream, or milk to drinks.
- If you take OTC, prescription, or herbal supplements discuss these with your doctor prior to the test.
- Cholesterol test results should be discussed with the health-care professional to determine if treatment of high cholesterol is necessary to decrease the risk of heart disease and stroke.
What is cholesterol?
Cholesterol is a naturally occurring fat that the body needs to produce important structures and chemicals. It is one of the main components of cell membranes, the outer lining that protects the internal structures that make body cells work and function properly. Cholesterol is also a building block for many of the hormones in the body including mineralocorticoids that control electrolyte levels in the body, glucocorticoids involved in carbohydrate metabolism, and sex hormones including testosterone, estrogen, and progesterone. Cholesterol is one of the building blocks that assists in forming vitamin D in the body. Vitamin D is responsible for calcium metabolism in the body.
There are two important types of cholesterol, high density lipoprotein (HDL) and low density lipoprotein (LDL). LDL is the bad cholesterol that deposits in arteries when too much is present. HDL is considered the good cholesterol because it can bind to LDL cholesterol and return it to the liver where it can be removed from the body.
While most of the cholesterol in the body is obtained through the foods we eat, it is also produced in the liver to meet the body's demands. The body attempts to regulate the amount of total cholesterol, but when too much cholesterol is present, the excess can be deposited in arteries throughout the body. This leads to artery narrowing and increases the risk of heart attack, stroke, and peripheral vascular disease. Elevated LDL levels increase the risk of these diseases, and elevated HDL levels decrease the risk.