Also known as:TG; TRIG
Related tests:Cholesterol; HDL Cholesterol; LDL Cholesterol; Direct LDL Cholesterol; VLDL Cholesterol; Lipid Profile; Cardiac Risk Assessment
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Why Get Tested?
To assess your risk of developing heart disease; to monitor effectiveness of lipid-lowering therapy
When to Get Tested?
Screening: as part of a lipid profile during a regular medical exam at least once every four to six years for adults; for children, at least once between the ages of 9 and 11 and again between the ages of 17 and 21
Monitoring: may be done more frequently if you have risk factors for heart disease and/or if you are being treated for unhealthy lipid levels
A blood sample drawn from a vein in your arm or from a fingerstick
Test Preparation Needed?
Current standards recommend that testing be done when you are fasting. For 9 to 12 hours before the test, only water is permitted. In addition, alcohol should not be consumed for 24 hours just before the test. Your healthcare practitioner may decide that you may be tested without fasting. Follow any instructions you are given and tell the person drawing your blood whether or not you have fasted.
How is it used?
Blood tests for triglycerides are usually part of a Lipid Profile that is used to help identify an individual's risk of developing heart disease and to help make decisions about what treatment may be needed if there is borderline or high risk. As part of a lipid profile, it may be used to monitor people who have risk factors for heart disease, those who have had a heart attack, or those who are being treated for high lipid and/or high triglyceride levels.
Results of the cholesterol test and other components of the lipid profile are used along with other known risk factors of heart disease to develop a plan of treatment and follow-up. Treatment options may include lifestyle changes, such as diet or exercise programs, or lipid-lowering drugs, such as statins.
When is it ordered?
A Lipid Profile, which includes triglycerides, is recommended every 4 to 6 years to evaluate risk of heart disease in healthy adults. Children should have a lipid profile screening at least once between the ages of 9 and 11 and once again between the ages of 17 and 21.
Testing may be ordered more frequently when people have identified risk factors for heart disease. Some risk factors for heart disease include:
- Cigarette smoking
- Being overweight or obese
- Unhealthy diet
- Being physically inactive–not getting enough exercise
- Age (men 45 years or older or women 55 years or older)
- High blood pressure (hypertension–blood pressure of 140/90 or higher or taking high blood pressure medication)
- Family history of premature heart disease (heart disease in an immediate family member–male relative under age 55 or female relative under age 65)
- Pre-existing heart disease or already having had a heart attack
- Diabetes or prediabetes
For diabetics, it is especially important to have triglycerides measured as part of any lipid testing since triglycerides increase significantly when blood glucose levels are not well-controlled.
Screening for high cholesterol as part of a lipid profile is recommended for children and young adults. They should be tested once between the ages of 9 and 11 and then again between the ages of 17 and 21. Earlier and more frequent screening with a lipid profile is recommended for children and youths who are at an increased risk of developing heart disease as adults. Some of the risk factors are similar to those in adults and include a family history of heart disease or health problems such as diabetes, high blood pressure, or being overweight.
High-risk children should have their first cholesterol test between 2 and 8 years old, according to the American Academy of Pediatrics. Children younger than 2 years old are too young to be tested.
As part of a lipid profile, triglycerides tests may be ordered at regular intervals to evaluate the success of lipid-lowering lifestyle changes, such as diet and exercise, or to determine the effectiveness of drug therapy such as statins. Guidelines from the American College of Cardiology and the American Heart Association recommend that adults taking statins have a fasting lipid profile done 4 to 12 weeks after starting therapy and then every 3 to 12 months thereafter to assure that the drug is working.
What does the test result mean?
In general, healthy lipid levels help to maintain a healthy heart and lower the risk of heart attack or stroke. A healthcare practitioner will take into consideration the results of each component of the lipid profile as well as other risk factors to help determine a person's overall risk of heart disease, whether treatment is necessary and, if so, which treatment will best help to lower the person's risk.
In 2002, the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATPIII) provided the guidelines for evaluating lipid levels and determining treatment. In 2013, the American College of Cardiology and the American Heart Association issued guidelines for adults that made recommendations on who should receive cholesterol-lowing therapy. (For more details, see the Lipid Profile article).
However, use of the updated guidelines remains controversial. Many still use the older guidelines from the NCEP ATP III to evaluate lipid levels and cardiovascular disease risk:
For adults, triglyceride test results are categorized as follows:
- Desirable: Less than 150 mg/dL (1.7 mmol/L)
- Borderline high: 150 to 199 mg/dL (1.7-2.2 mmol/L)
- High: 200 to 499 mg/dL (2.3-5.6 mmol/L)
- Very high: Greater than 500 mg/dL (5.6 mmol/L)
For children, teens and young adults:
From newborn to age 9
- Acceptable: Less than 75 mg/dL (0.85 mmol/L)
- Borderline high: 75-99 mg/dL (0.85-1.12 mmol/L)
- High: Greater than 100 mg/dL (1.13 mmol/L)
For ages 10-19 years
- Acceptable: Less than 90 mg/dL (1.02 mmol/L)
- Borderline high: 90-129 mg/dL (1.02-1.46 mmol/L)
- High: Greater than 130 mg/dL (1.47 mmol/L)
For young adults older than 19
- Acceptable: Less than 115 mg/dL (1.30 mmol/L)
- Borderline high: 115-149 mg/dL (1.30-1.68 mmol/L)
- High: Greater than 150 mg/dL (1.7 mmol/L)
Note: These values are based on fasting triglyceride levels.
When triglycerides are very high (greater than 1000 mg/dL (11.30 mmol/L)), there is a risk of developing pancreatitis in children and adults. Treatment to lower triglycerides should be started as soon as possible.
Is there anything else I should know?
If you are diabetic and your blood sugar (glucose) is out of control, triglycerides may be very high.
Triglycerides change dramatically in response to meals, increasing as much as 5 to 10 times higher than fasting levels just a few hours after eating. Even fasting levels vary considerably day to day. Therefore, modest changes in fasting triglycerides measured on different days are not considered to be abnormal.
Certain drugs such as corticosteroids, protease inhibitors for HIV, beta blockers, and estrogens can increase blood triglyceride levels.
There is increasing interest in measuring triglycerides in people who have not fasted. The reason is that a non-fasting sample may be more representative of the "usual" circulating level of triglyceride since most of the day blood lipid levels reflect post-meal (post-prandial) levels rather than fasting levels. However, it is not yet certain how to interpret non-fasting levels for evaluating risk so, at present, there is no change in the current recommendations for fasting prior to tests for lipid levels.
What is being tested?
Triglycerides are a form of fat and a major source of energy for the body. This test measures the amount of triglycerides in the blood.
Most triglycerides are found in fat (adipose) tissue, but some triglycerides circulate in the blood to provide fuel for muscles to work. After a person eats, an increased level of triglycerides is found in the blood as the body converts the energy not needed right away into fat. Triglycerides move via the blood from the gut to adipose tissue for storage. In between meals, triglycerides are released from fat tissue to be used as an energy source for the body. Most triglycerides are carried in the blood by lipoproteins called very low-density lipoproteins (VLDL).
High levels of triglycerides in the blood are associated with an increased risk of developing cardiovascular disease (CVD), although the reason for this is not well understood. Certain factors can contribute to high triglyceride levels and to risk of CVD, including lack of exercise, being overweight, smoking cigarettes, consuming excess alcohol, and having medical conditions such as diabetes and kidney disease.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm. Sometimes, a drop of blood is collected by puncturing the skin on a fingertip. This fingerstick sample is typically used when a Lipid Profile (total cholesterol, HDL-C, LDL-C and TG) is being measured on a portable testing device, for example, at a health fair.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
Current standards recommend that testing be done when you are fasting. For 9 to 12 hours before the test, only water is permitted. Your healthcare practitioner may decide that you may be tested without fasting. Follow any instructions you are given and tell the person drawing your blood whether or not you have fasted. In addition, alcohol should not be consumed for 24 hours just before the test.
- What strategies can be used to lower triglyceride levels?
For many people, high triglycerides are caused by another disorder, such as diabetes, obesity, renal failure, or alcoholism. With these conditions, the strategy is to treat the primary cause. When high triglycerides are not caused by another disorder, they are often seen together with high Cholesterol and treatment is directed toward lowering both cholesterol and triglycerides. Lifestyle changes, such as a healthy diet and increased exercise, are usually the primary strategy for lowering levels. If these fail, lipid-lowering medications such as statins are generally recommended. For more on this, visit the American Heart Association's webpage on Healthy Living.
- Can I monitor triglyceride levels at home?
A few products are available to test lipid levels, including triglycerides, at home. There are two types of home testing: those where you collect the sample at home and then mail it away to a laboratory for testing and those where you conduct the test yourself at home (self-monitoring). The American Heart Association hasn't taken a position on the use of home testing devices for measuring lipid levels. Before making the decision to use one of these products, you may want to review the article about home testing on this site: With Home Testing, Consumers Take Charge of Their Health.
- What is VLDL and how does it relate to triglyceride?
Very low-density lipoprotein (VLDL) is one of the major lipoprotein particles. Others include high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Each one of these particles contains a mixture of cholesterol, protein, and triglyceride but in varying amounts unique to each type of particle. LDL contains the highest amount of cholesterol. HDL contains the highest amount of protein. VLDL contains the highest amount of triglyceride. Since VLDL contains most of the circulating triglyceride and since the compositions of the different particles are relatively constant, it is possible to estimate the amount of VLDL-cholesterol by dividing the triglyceride value (in mg/dL) by 5. At present, there is no simple, direct way of measuring VLDL-cholesterol, so the estimate calculated from triglyceride is used in most settings. This calculation is not valid when the triglyceride is greater than 400 mg/dL. Increased levels of VLDL-cholesterol have been found to be associated with increased risk of heart disease and stroke.
- Are there any symptoms associated with a high level of triglycerides?
Usually, most people with high triglyceride levels have no symptoms and the only means of discovering a high level is with blood tests. However, in rare cases, a person may have an extremely high level of triglycerides (well above 1000 mg/dL) sustained over time and the individual may experience repeated bouts of acute pancreatitis. Some of the signs and symptoms include pain in the upper half of the stomach area that develops suddenly and then gradually gets worse, fever, nausea, vomiting, and sometimes jaundice. A person with severely high levels may also develop lesions on the skin called xanthomas. These typically appear as several small, round, solid, yellow bumps mostly on the back, chest, buttocks, shoulders and thighs.
© 2017 American Association for Clinical Chemistry, republished from Lab Tests Online.*
Descriptions of clinical laboratory tests were originally prepared for use on Lab Tests Online, an award-winning patient education website on clinical laboratory testing. Lab Tests Online is produced by the American Association for Clinical Chemistry (AACC), a global scientific and medical professional organization dedicated to clinical laboratory science and its application to healthcare. The Lab Tests Online website is developed in collaboration with other laboratory professional societies and is funded in part through corporate sponsorships.