What is a cholesterol test?

A cholesterol test is a blood test that measures the amount of cholesterol and triglycerides (a type of fat) in your blood. Cholesterol is a waxy, fat-like substance that's found in your blood and every cell of your body. Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods.

Your liver makes all the cholesterol your body needs and removes excess amounts. Cholesterol is also found in foods from animal sources, such as meat, egg yolks, poultry, and dairy products. Foods high in dietary fat can increase the cholesterol in your blood. If there's too much cholesterol in your blood, your liver can't remove it all.

There are two main types of cholesterol: LDL (low-density lipoprotein), or "bad" cholesterol, and HDL (high-density lipoprotein), or "good" cholesterol.

Too much LDL cholesterol in your blood increases your risk for coronary artery disease and other heart diseases. High LDL levels can cause the buildup of a sticky substance called plaque in your arteries. This buildup of plaque is known as atherosclerosis. Over time, plaque can narrow your arteries or fully block them. When this happens, parts of your body may not get enough blood:

• If the blood flow to your heart is blocked, it can cause a heart attack.
• If the blood flow to your brain is blocked, it can cause a stroke.
• If the blood flow to your arms or legs is blocked, it can cause peripheral artery disease.

Other names for a cholesterol test: Lipid profile, Lipid panel

What is it used for?

A cholesterol test gives you and your health care provider important information about your risk of developing heart disease. If your test shows you have high cholesterol, you can take steps to lower it. This may decrease your risk of developing heart problems in the future.

A cholesterol test measures your:

• LDL level. LDL ("bad") cholesterol is the main source of blockages in the arteries.
• HDL level. HDL ("good') cholesterol helps get rid of "bad" LDL cholesterol. A higher HDL level may help reduce your risk of heart attack or stroke.
• Total cholesterol. This is a measure of the total amount of cholesterol in your blood. It includes HDL and LDL cholesterol.
• Triglyceride level. Triglycerides are a type of fat found in your blood. High levels of triglycerides may increase the risk of heart disease, especially in women.

There is another type of cholesterol called VLDL (very low-density lipoprotein). Some people also call VLDL a "bad" cholesterol because it contributes to the buildup of plaque in your arteries. But VLDL and LDL are different; VLDL mainly carries triglycerides, and LDL mainly carries cholesterol. VLDL isn't usually included in routine cholesterol tests because it's difficult to measure. Because VLDL contains a certain percentage of triglycerides, a lab can use your triglycerides level to estimate your VLDL level.

Why do I need a cholesterol test?

Your provider may order a cholesterol test as part of a routine exam. When and how often you should get a cholesterol test depends on your age, risk factors, and family history. The general recommendations are:

For people who are age 19 or younger:

• The first test should be between ages 9 to 11
• Children should have the test again every 5 years
• Some children may have this test starting at age 2 if there is a family history of high cholesterol, heart attack, or stroke

For people who are ages 20 to 65:

• Younger adults should have the test every 5 years
• Men ages 45 to 65 and women ages 55 to 65 should have it every 1 to 2 years

For people older than 65:

• They should be tested every year

You may also have a cholesterol test more often if you are at high risk of heart problems because of:

• A family history of heart disease
• High blood pressure
• Type 2 diabetes
• Smoking
• Excess weight or obesity
• Lack of physical activity
• A diet high in saturated fat

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.

You may be able to use an at-home kit to check your cholesterol levels. Your kit will include a device to prick your finger to collect a drop of blood for testing. Be sure to follow the kit instructions carefully. Also, be sure to tell your provider if your at-home test shows that your total cholesterol level is higher than 200 mg/dl.

Will I need to do anything to prepare for the test?

You may need to fast (not eat or drink) for 9 to 12 hours before your blood cholesterol test. That's why the tests are often done in the morning. Your provider will let you know if you need to fast and if there are any other special instructions.

Are there any risks to the test?

There is very little risk to having a blood test. You may experience slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

Cholesterol is usually measured in milligrams (mg) of cholesterol per deciliter (dL) of blood. The information below will help you understand what your test results mean. In general, low LDL levels and high HDL cholesterol levels are good for heart health.

Anyone age 19 or younger:

Men age 20 or older:

Women age 20 or older:

The LDL listed on your results may say "calculated." This means that your LDL level is an estimate based on your total cholesterol, HDL, and triglycerides. Your LDL level may also be measured "directly" from your blood sample. Either way, you want your LDL number to be low.

A healthy cholesterol level for you may depend on your age, family history, lifestyle, and other risk factors for heart disease, such as high triglyceride levels. Your provider can explain what's right for you.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about my cholesterol levels?

High cholesterol can lead to heart disease, the number one cause of death in the United States. You can't change some risk factors for high cholesterol, such as age and your genes. But there are actions you can take to lower your LDL levels and reduce your risk, including:

• Eat a healthy diet. Reduce or avoid foods high in saturated fat and cholesterol to help lower the cholesterol levels in your blood.
• Manage your weight. Being overweight can increase your cholesterol and risk for heart disease.
• Stay active. Regular physical activity may help lower your LDL (bad) cholesterol levels and raise your HDL (good) cholesterol levels. It may also help you lose weight.
• Quit smoking. Smoking lowers your HDL (good) cholesterol, especially in women. Smoking also raises your LDL (bad) cholesterol.
• Reduce stress. Stress may raise levels of certain hormones such as corticosteroids. These can cause your body to make more cholesterol.
• Avoid drinking too much alcohol. Alcohol can raise your total cholesterol level.

Talk to your provider before making any major change in your diet or exercise routine.