Cholesterol Test

What is the blood cholesterol (lipid panel) test?

A blood cholesterol test (lipid panel) usually measures 3 different kinds of lipids in the blood, all of which are related to a fatlike substance called cholesterol. Most of the cholesterol in your blood is made by your liver from the fats, carbohydrates, and proteins you eat. You also get cholesterol by eating animal products such as meat, eggs, and dairy products.

The 3 kinds of lipids measured in a lipid panel are:

• LDL cholesterol (low-density lipoprotein)
• HDL cholesterol (high-density lipoprotein)
• triglycerides.

The lipid panel also measures total cholesterol, which is the sum of all the types of cholesterol in your blood.

Another name for this test is lipid profile.

Why is this test done?

The lipid panel helps check your risk for heart disease or atherosclerosis, which is a hardening, narrowing, or blockage of the arteries.

Your risk is increased if you have:

• high levels of total cholesterol, LDL, and triglycerides
• a low level of HDL.

Your risk is decreased if you have:

• low levels of total cholesterol LDL, and triglycerides
• a high level of HDL.

LDL cholesterol is called bad cholesterol because the higher your LDL, the greater your risk for heart disease. HDL is called good cholesterol because a high level of HDL in your blood reduces your risk. HDL attaches to and carries away other lipids, such as LDL cholesterol. HDL makes it harder for the LDL to stick to the walls of your blood vessels and cause hardening of the arteries.

High triglycerides may be related to heart disease, but not as much is known yet about triglycerides and heart disease. When triglycerides are high, HDL is often low.

High levels of total cholesterol in your blood increase your risk of heart disease.

Because high cholesterol itself does not cause symptoms, you may not know that your cholesterol level is too high. If this test shows that you have high cholesterol, you can start treatment to lower it and decrease your chances of heart disease. If you already have heart disease, treatment to reduce your level of cholesterol can still reduce your chances of a first or repeat heart attack and lower your risk of death from heart disease.

If you have changed your diet and exercise habits or are taking medicine to lower your cholesterol levels, this test can show how well your treatment is working.

How do I prepare for this test?

• Many lipid levels are affected by fat in your diet. Avoid eating fatty foods the evening before your test.
• You should fast overnight before you have this test. This means you should not eat or drink anything after midnight the night before your test. Eating food within 9 to 12 hours before the test will not affect the HDL or total cholesterol test results, but it may affect the test results for triglycerides and LDL. If you need to take medicines, you may take them with a small amount of water on the morning of your test.
• Don't drink any alcohol for 24 hours before the test.
• Avoid exercise for 12 to 14 hours before the test.
• You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your health care provider knows about any medicines, herbs, or supplements that you are taking. Don't stop any of your regular medicines without first consulting with your health care provider.
• Talk to your health care provider if you have any questions.

How is the test done?

A small amount of blood is taken from your arm with a needle. The blood is collected in tubes and sent to a lab.

Having this test will take just a few minutes of your time. There is no risk of getting AIDS, hepatitis, or any other blood-borne disease from this test.

How will I get the test result?

Ask your health care provider when and how you will get the result of your test.

What do the test results mean?

Total Cholesterol Level (mg/dL)

LDL: Ask your provider about your risk for heart disease. It will help you know what your LDL goal should be.

• If you have a low risk of heart disease, the recommended level of LDL is less than 160 mg/dL.
• If you have a moderate risk for heart disease, your goal is less than 130 mg/dL.
• If you have heart disease, diabetes, or a high risk of heart disease, your LDL should be below 100 mg/dL.

HDL: Because HDL cholesterol protects against heart disease, higher numbers are better. A level less than 40 mg/dL is low and is considered a major risk factor because it increases your risk for developing heart disease. HDL levels of 60 mg/dL or more help to lower your risk for heart disease.

Triglycerides (mg/dL)

Your LDL cholesterol, triglycerides, or total cholesterol levels may be high, or your HDL cholesterol level may be low, because :

• You have an inherited tendency to have abnormal levels of lipids.
• You smoke.
• You don't get enough exercise.
• You eat too much saturated (animal) fat.
• You have hypothyroidism.
• You take certain medicines or vitamins, such as anabolic steroids, beta blockers, epinephrine, birth control pills, or vitamin D.

What if my test result is not normal?

Test results are only one part of a larger picture that takes into account your personal and family medical history and your current health. Sometimes a test needs to be repeated to check the first result. Talk to your health care provider about your result and ask questions.

If your test results are not normal, ask your health care provider:

• if you need additional tests
• what you can do to work toward a normal value
• when you need to be tested again.

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