Triglycerides are a type of fat. Your body makes some triglycerides. Triglycerides also come from the food you eat. A blood test can be done to measure the amount of triglycerides in your blood. This is called a triglyceride level.

When you eat, your body uses calories for immediate energy. Leftover calories are turned into triglycerides and stored in fat cells for later use. If you eat more calories than your body needs, your triglyceride level may be high.

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

You should not eat for 8 to 12 hours before the test.

Certain drugs may affect test results. Make sure your doctor knows what medicines you take, including over-the-counter drugs and supplements. Your doctor may tell you to temporarily stop taking certain medicines. Never stop taking any medicine without first talking to your doctor.

Drugs that can increase triglyceride measurements include cholestyramine, estrogens, and birth control pills.

Drugs that can decrease triglyceride measurements include ascorbic acid, asparaginase, clofibrate, colestipol, fenofibrate, fish oil, gemfibrozil, nicotinic acid, and statin medications.

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

This test is often done to determine your risk of developing heart disease. A high triglyceride level may lead to atherosclerosis, which increases your risk of heart attack and stroke.

Persons with high triglycerides often have other conditions, such as diabetes and obesity, that also increase the chances of developing heart disease.

The triglyceride level is usually included in a coronary risk (lipid) profile.

• Normal: Less than 150 mg/dL
• Borderline High: 150-199 mg/dL
• High: 200-499 mg/dL
• Very High: 500 mg/dL or above

High triglyceride levels may be due to:

• Cirrhosis
• Diet low in protein and high in carbohydrates
• Familial hyperlipoproteinemia (rare)
• Hypothyroidism
• Nephrotic syndrome
• Pancreatitis
• Poorly controlled diabetes

Low triglyceride levels may be due to:

• Low fat diet
• Hyperthyroidism
• Malabsorption syndrome
• Malnutrition

Additional conditions under which the test may be performed:

• Chylomicronemia syndrome
• Hyperlipidemia; acquired
• Familial combined hyperlipidemia
• Familial dysbetalipoproteinemia
• Familial hypertriglyceridemia
• Familial lipoprotein lipase deficiency
• Noninsulin-dependent diabetes (NIDD)
• Stroke secondary to atherosclerosis
• Stroke secondary to carotid stenosis

Veins and arteries vary in size from one patient to another, and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. Other risks may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Pregnancy can interfere with test results.

Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). JAMA. 2001 May 16;285(19):2486-97.