EBSCO Health

Print PageSend to a Friend
Health Library Home>Article


(TG; TRIG; Triacylglycerol)

What Are Triglycerides?

Triglycerides are a fat-like substance. Muscles need them for energy. Extra triglycerides move around in the blood and are stored as fat. Eating too many calories makes the blood level higher. Higher levels of triglycerides are linked to a higher risk of heart disease and stroke.

Reason for the Test

A test checks the triglyceride level in the blood. The test may done:

  • As part of a routine checkup
  • As part of a lipid profile that checks different types of cholesterol levels in the blood
  • To track levels if you have other health problems such as diabetes or are at high risk for heart disease
  • To see if treatment is working as it should

Type of Sample Taken

A blood sample will be taken from a vein in the arm.

Prior to Collecting the Sample

You need to fast 8 to 12 hours before the test.

Tell your doctor about any medicines or supplements you are taking. They may affect the test results.

During the Sample Collection

You will be asked to sit. An area inside your elbow will be cleaned. A large band will be tied around your arm. The needle will then be inserted into a vein. A tube will collect the blood from the needle. The band on your arm will be removed. Once all the blood is collected, the needle will be removed. Some gauze will be placed over the site to help stop bleeding. You may also be given a bandage to place over the site. The process takes about 5 to 10 minutes.

After Collecting the Sample

After the blood sample is taken, you may need to stay seated for 10 to 15 minutes. If you are lightheaded, you may need to stay seated longer. When you feel better, you can leave.

A bit of blood may ooze from the vein beneath the skin. It will cause a bruise. Firm pressure over the site after the needle is removed will decrease the chance of a bruise. A bruise will usually fade in a day or 2.

Call your doctor right away if you have redness, swelling, lasting bleeding, or pain.


Results can take many days to many weeks. Normal ranges differ by age. The risk of heart disease or stroke gets higher as triglyceride levels rise. You may need treatment if it is high enough.

High triglyceride levels are linked to:

  • Metabolic syndrome—if blood glucose and blood pressure are also higher than normal
  • A diet high in fats and carbohydrates, and low in proteins
  • Excess weight and lack of activity
  • Nephrotic syndrome
  • Underactive thyroid
  • Diabetes that is not controlled
  • Pancreatitis—the risk gets higher as levels rise
  • Liver disease
  • Gout
  • Glycogen storage disease

Low triglyceride levels are linked to:

  • Malnutrition
  • Overactive thyroid
  • End-stage liver disease
  • Hypolipoproteinemia and abetalipoproteinemia

Your doctor will talk to you about the results. A test may point to an illness that you do not have. It can also miss an illness that you may have. The doctor will check your symptoms and all test results before making a diagnosis.


Triglycerides. Lab Tests Online—American Association for Clinical Chemistry website. Available at: https://labtestsonline.org/tests/triglycerides. Updated July 22, 2019. Accessed July 29, 2019.

Trigylcerides measurement. EBSCO DynaMed website. Available at:https://www.dynamed.com/lab-monograph/drugs-of-abuse-urine-screening-test. Updated November 7, 2018. Accessed July 29, 2019.

Last reviewed June 2019 by EBSCO Medical Review Board Nicole S. Meregian, PA  Last Updated: 10/25/2019