A triglyceride level is a blood test that measures a type of fat in the blood. Triglycerides are different from cholesterol, which is often measured at the same time.
Who is a candidate for the test?
A triglyceride level may be ordered to see how well the body processes fats. It is usually ordered as part of a lipid profile to help evaluate risk factors for coronary heart disease (CHD).
Triglyceride levels are an independent risk factor for coronary heart disease. This means that a person's risk for CHD is increased whenever triglyceride levels are high, regardless of the person's cholesterol level.
How is the test performed?
To perform a triglyceride level, a blood sample is needed. Blood is usually taken from a vein on the forearm or hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube, or tourniquet, is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow. A fine needle is gently inserted into a vein, and the tourniquet is removed. Blood flows through the needle and is collected in a syringe or vial. After the needle is withdrawn, the puncture site is covered for a short time to prevent bleeding. The blood is then sent to the lab for testing.
What is involved in preparation for the test?
An individual is often asked not to eat anything for at least 10 or 12 hours prior to the test.
What do the test results mean?
Triglyceride levels are defined as follows:
- normal is less than 150 mg/dL
- 150-199 mg/dL is borderline high
- 200-499 mg/dL indicates high triglycerides
- 500 mg/dL or above indicates a very high triglyceride level
Abnormally high triglyceride levels may be due to:
- alcohol abuse
- some kinds of kidney diseases
- hypothyroidism, or an underactive thyroid gland
- inflammation of the pancreas, which in turn may be caused by high levels of triglycerides
- an inherited, impaired ability to process fats that results in high levels of fats in the blood
- lack of physical activity
- overweight or obesity
- certain medicines, including corticosteroids and estrogen
Abnormally low triglyceride levels may indicate the following:
- impaired absorption of nutrients in the intestine
- severe liver disease