What is a cholesterol test?
Cholesterol is a waxy, fat-like substance that's found in your blood and every cell of your body. You need some cholesterol to keep your cells and organs healthy. Your liver makes all the cholesterol your body needs. But you can also get cholesterol from the foods you eat, especially meat, eggs, poultry, and dairy products. Foods that are high in dietary fat can also make your liver produce more cholesterol.
There are two main types of cholesterol: low-density lipoprotein (LDL), or "bad" cholesterol, and high-density lipoprotein (HDL), or "good" cholesterol. A cholesterol test is a blood test that measures the amount of each type of cholesterol and certain fats in your blood.
Too much LDL cholesterol in your blood may put you at risk for heart disease and other serious conditions. High LDL levels can cause the build-up of plaque, a fatty substance that narrows the arteries and blocks blood from flowing normally. When blood flow to the heart is blocked, it can cause a heart attack. When blood flow to the brain is blocked, it can lead to stroke and peripheral artery disease.
Other names for a cholesterol test:
Lipid profile, Lipid panel
What is it used for?
If you have high cholesterol, you may not experience any symptoms at all, but you could be at significant risk for heart disease. A cholesterol test can give your health care provider important information about the cholesterol levels in your blood. The test measures:
- LDL levels. Also known as the "bad" cholesterol, LDL is the main source of blockages in the arteries.
- HDL levels. Considered the "good" cholesterol, HDL helps get rid of "bad" LDL cholesterol.
- Total cholesterol. The combined amount of low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol in your blood.
- Triglycerides A type of fat found in your blood. According to some studies, high levels of triglycerides may increase the risk of heart disease, especially in women.
- VLDL levels. Very low-density lipoprotein (VLDL) is another type of "bad" cholesterol. Development of plaque on the arteries has been linked to high VLDL levels. It's not easy to measure VLDL, so most of the time these levels are estimated based on triglyceride measurements.
Why do I need a cholesterol test?
Your doctor may order a cholesterol test as part of a routine exam, or if you have a family history of heart disease or one or more of the following risk factors:
- High blood pressure
- Type 2 diabetes
- Excess weight or obesity
- Lack of physical activity
- A diet high in saturated fat
Your age may also be a factor, because your risk for heart disease increases as you get older.
What happens during a cholesterol test?
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
Cholesterol tests are usually done in the morning, as you may be asked to refrain from eating for several hours prior to the test.
You may also be able to use an at-home kit to test for cholesterol. While instructions may vary between brands, your kit will include some kind of device to prick your finger. You’ll use this device to collect a drop of blood for testing. Be sure to follow the kit instructions carefully.
Also, be sure to tell your health care provider if your at-home test results show your cholesterol level is higher than 200 mg/dl.
Will I need to do anything to prepare for the test?
You may need to fast--no food or drink--for 9 to 12 hours before your blood is drawn. Your health care provider will let you know if you need to fast and if there are any special instructions to follow.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruise at the spot where the needle was put in, but most symptoms go away quickly.