Cholesterol and Triglycerides Tests

	Test Overview
	Health Tools
	Why It Is Done
	How To Prepare
	How It Is Done
	How It Feels
	Risks
	Results
	What Affects the Test
	What To Think About
	References
	Credits

Cholesterol and triglyceride tests are blood tests that measure the total amount of fatty substances (cholesterol and triglycerides) in the blood.

Cholesterol travels through the blood attached to a protein. This cholesterol-protein package is called a lipoprotein. Lipoprotein analysis (lipoprotein profile or lipid profile) measures blood levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.

• Cholesterol. The body uses cholesterol to help build cells and produce hormones. Too much cholesterol in the blood can build up along the inside of the artery walls, forming what is known as plaque. Large amounts of plaque increase your chances of having a heart attack or stroke.
• HDL (high-density lipoprotein) cholesterol helps remove fat from the body by binding with it in the bloodstream and carrying it back to the liver for disposal. It is sometimes called "good" cholesterol. A high level of HDL cholesterol may lower your chances of developing heart disease or stroke.
• LDL (low-density lipoprotein) cholesterol carries mostly fat and only a small amount of protein from the liver to other parts of the body. It is sometimes called "bad cholesterol." A high LDL cholesterol level may increase your chances of developing heart disease.
• VLDL: (very low-density lipoprotein) cholesterol contains very little protein. The main purpose of VLDL is to distribute the triglyceride produced by your liver. A high VLDL cholesterol level can cause the buildup of cholesterol in your arteries and increases your risk of heart disease and stroke.
• Triglycerides are a type of fat the body uses to store energy. Only small amounts are found in the blood. Having a high triglyceride level along with a high LDL cholesterol may increase your chances of having heart disease more than having only a high LDL cholesterol level.

Some medical experts recommend routine cholesterol and triglyceride testing to screen for problems that affect the way cholesterol is produced, used, carried in the blood, or disposed of by the body. Others may choose to routinely measure only total cholesterol and HDL levels.

• National Cholesterol Education Panel (NCEP) guidelines for cholesterol screening
• U.S. Preventive Services Task Force (USPSTF) guidelines for cholesterol screening
• American College of Physicians (ACP) guidelines for cholesterol screening

Health tools help you make wise health decisions or take action to improve your health.

	Interactive tools are designed to help people determine health risks, ideal weight, target heart rate, and more.
	Interactive Tool: Are You at Risk for a Heart Attack?

Cholesterol and triglyceride testing is done:

• As part of a routine physical exam to screen for a lipid disorder.
• To check your response to medicines used to treat lipid disorders.
• To help determine your chances of having of heart disease, especially if you have other risk factors for heart disease or symptoms that suggest heart disease is present.
• If you have unusual symptoms, such as yellow fatty deposits in the skin (xanthomas), which may be caused by a rare genetic disease that causes very high cholesterol levels.

Preparation depends on the test. Ask your doctor which test you are having. For example, you can get a total cholesterol test or direct LDL test at any time, even if you recently had a meal or a snack. But you will likely not eat for a few hours before a test that measures LDL, HDL, and triglycerides.

• If your doctor tells you to fast before your test, do not eat or drink anything except water for 9 to 12 hours before having your blood drawn. Usually, you are allowed to take your medicines with water the morning of the test. Fasting is not always necessary, but it may be recommended.
• Do not eat high-fat foods the night before the test.
• Do not drink alcohol or exercise strenuously before the test.

Many medicines may affect the results of this test. Be sure to tell your health professional about all the nonprescription and prescription medicines and herbs or natural substances you take.

Tell your health professional if you have had a test such as a thyroid or bone scan that uses a radioactive substance within the last 7 days.

Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will indicate. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

The health professional taking a sample of your blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Put a gauze pad or cotton ball over the needle site as the needle is removed.
• Put pressure on the site and then put on a bandage.

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your health professional before your blood sample is taken.

Cholesterol and triglyceride tests are blood tests that measure the total amount of fatty substances (cholesterol and triglycerides) in the blood.

Results are usually available within 24 hours.

Cholesterol and triglyceride levels vary according to your age and sex. Results may also vary from lab to lab.

• An HDL level of 60 mg/dL (1.5 mmol/L) or higher protects against heart disease.
• HDL cholesterol levels of 40 mg/dL (1.0 mmol/L) or lower increase your risk of developing heart disease, especially if you also have high total cholesterol levels.
• Very high cholesterol and triglyceride levels may be caused by an inherited form of high cholesterol (hypercholesterolemia or hyperlipidemia).
• If you have a very high risk of having a heart attack, your doctor may want your LDL level to be less than 70 mg/dL. You have a very high risk if you smoke and have coronary artery disease, or if you have coronary artery disease and diabetes, acute coronary syndrome, or metabolic syndrome.

Many conditions can affect cholesterol and triglyceride levels. Your health professional will talk with you about any abnormal results that may be related to your other health problems.

Reasons you may not be able to have the test or why the results may not be helpful include:

• Medicines, such as diuretics, corticosteroids, male sex hormones (androgens), tranquilizers, estrogen, birth control pills, antibiotics, and niacin (vitamin B3).
• Physical stress, such as infection, heart attack, surgery.
• Eating 9 to 12 hours before the test.
• Other conditions, such as hypothyroidism, diabetes, or kidney or liver disease.
• Alcohol or drug abuse or withdrawal.
• Liver disease (such as cirrhosis or hepatitis), malnutrition, or hyperthyroidism.
• Pregnancy. Values are the highest during the third trimester and usually return to the prepregnancy levels after delivery of the baby.

• Having a high cholesterol level increases your chances of having a heart attack. The higher your cholesterol, the greater your chances. An elevated total cholesterol level in younger people is particularly significant, since the narrowing of the coronary arteries usually takes many years to develop.
• Lifestyle changes (such as diet changes, weight loss, and exercise) may help lower blood cholesterol levels and increase HDL ("good") cholesterol. Some people have better responses to diet and lifestyle changes than do others. Lifestyle changes might include:
  • Reducing saturated (animal) fats and cholesterol in the diet while increasing fiber and complex carbohydrate.
  • Losing weight. An improvement may occur if you lose as little as 5 lb (2.5 kg) to 10 lb (4.5 kg).
• Moderate consumption of alcohol can also increase HDL cholesterol.
  • Moderate alcohol consumption means no more than 2 drinks per day for men or 1 drink per day for women; 1 drink is 12 fl oz (350 mL) of beer, 5 fl oz (150 mL) of wine, or 1.5 fl oz (45 mL) of liquor.
  • The benefits of alcohol consumption must be balanced against the increased risk of alcoholism, high blood pressure, heart problems such as atrial fibrillation and heart failure, and cirrhosis.
• The National Cholesterol Education Program (NCEP) has developed a risk assessment calculator to estimate your risk of having a heart attack or dying from coronary artery disease over 10 years. This tool is designed to estimate risk in adults age 20 and older who do not have heart disease or diabetes. Use the Interactive Tool: Are You at Risk for a Heart Attack? to calculate your risk of coronary artery disease.
• Talk with your doctor about other things that raise your risk for heart problems. Your doctor may change your goals for cholesterol levels if you have other risk factors for coronary artery disease, such as:
  • Smoking.
  • High blood pressure.
  • Diabetes.
  • Low HDL cholesterol (less than 40 mg/dL)
  • Family history of heart disease. You have a first-degree male relative (for example, your father or brother) who got CAD when he was younger than age 55. Or you have a first-degree female relative (for example, your mother or sister) who got CAD when she was younger than 65.
  • You are a man and older than 45, or you are a woman and older than 55.
• Talk to your health professional about which cholesterol screening is best for you. Medical experts disagree about routine screening for lipid disorders.
  • National Cholesterol Education Panel (NCEP) guidelines for cholesterol screening
  • U.S. Preventive Services Task Force (USPSTF) guidelines for cholesterol screening
  • American College of Physicians (ACP) guidelines for cholesterol screening
• Cholesterol screening is often available in supermarkets, pharmacies, shopping malls, and other public places. Home cholesterol testing kits also are available. The results of tests done outside a doctor's office or lab may not be accurate. If you have cholesterol screening done outside your doctor's office, talk with your doctor about the accuracy of the results.

Other Works Consulted

• Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.

• Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.

• Genest J, et al. (2003). Recommendations for the management of dyslipidemia and the prevention of cardiovascular disease: Summary of the 2003 update. Canadian Medical Association Journal, 169(9): 921–924. Also available online: http://www.cmaj.ca/cgi/content/full/169/9/921/DC1.

• Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.

• Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.