As part of a lipid profile during a medical examination, after a diagnosis of pancreatitis, or if you are being treated for high triglycerides
A blood sample taken from a vein in the arm
None. Fasting is not routinely required when checking triglyceride concentration (the guidance on this changed in 2014). However, there may be circumstances when fasting is still required, so follow your doctor's advice.
This test measures the amount of triglycerides in your blood. Triglycerides are the body's storage form of fat. Most triglycerides are found in fat (adipose) tissue, but some circulate in the blood to provide fuel for muscles to work. Extra triglycerides are found in the blood after eating a meal — when fat is being sent from the gut to fat tissue for storage.
How is the sample collected for testing?
Most often, a blood sample is collected using a needle to extract blood from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
The test for triglyceride can be performed without any special preparation. Previously, fasting for 12 hours was recommended, but this changed in 2014. As we spend many hours of the day in a "post-meal" state, triglyceride levels after a meal are just as valid a representation of what our body is exposed to as levels taken when fasting.
How is it used?
The most common reason for checking triglycerides is as part of a lipid profile to estimate risk of development cardiovascular disease. Triglycerides are a form of lipid (fat), and are therefore included as part of a lipid profile. However, unlike cholesterol, which is very clearly an important cause of cardiovascular disease, the relationship between triglycerides and cardiovascular disease is less clear. Overall, the evidence is somewhat (but not totally) in favour of a role for triglycerides here, as a number of scientific studies (but not all) have suggested that high triglycerides do increase the risk of cardiovascular disease. Therefore, most doctors would suggest that it is better to aim to keep your blood triglyceride concentrations low, particularly if you are at risk of cardiovascular disease for another reason.
Having high triglycerides can also lead to a serious medical condition called pancreatitis, which is inflammation of the pancreas gland. Therefore, if you get pancreatitis, triglyceride concentrations in the bloodstream should be checked to see if this is the cause. There are many other causes however.
When is it requested?
Lipid profile, including triglycerides, is commonly tested by your GP when you reach the age of 40, as part of a routine cardiovascular health check. It will also be checked if you are already thought to be at risk of cardiovascular disease for another reason, such as having diabetes, high blood pressure, being a smoker, or being overweight.
Due to the link between high triglycerides and pancreatitis, triglyceride concentrations will be checked if you are diagnosed with this condition.
What does the test result mean?
Having high triglycerides is thought to put you at higher risk of developing cardiovascular disease. It isn't totally clear whether it is the triglycerides themselves which are harmful, or an underlying condition, such as diabetes or obesity, which is the problem. Conditions such as these are known to increase cardiovascular risk directly, as well as cause high triglycerides. Trying to work out whether triglycerides cause cardiovascular disease, or are just associated with it, has been the subject of many scientific studies but the answer is not 100% clear at present.
If your triglyceride concentration is very high (e.g. at least 10-15 mmol/L), this indicates you are at risk of pancreatitis. In these circumstances, it is important to try and lower your triglyceride levels, which might involve either drugs or lifestyle changes, depending on the cause.
There are many factors which can cause high triglycerides. Examples include a high fat or high sugar diet, high intake of alcohol, obesity and diabetes. Lifestyle changes can therefore be effective in reducing triglyceride levels. Drug treatments are also available if lifestyle changes are insufficient. There are also genetic factors which increase triglyceride levels.
Is there anything else I should know?
If you are diabetic and your blood glucose cocentrations are out of control, triglyceride concentrations will be very high.
Triglyceride levels in the blood may change dramatically after a meal. Even fasting levels vary considerably from day to day. Because of the day to day variation modest changes in fasting triglycerides measured on different days are not considered to be unusual or abnormal.
Don't I need to fast before having my triglycerides measured?
Previously, fasting for 12 hours was recommended, as triglycerides increase after a meal for several hours. However, studies now show that readings after a meal are just as useful as fasting levels. There may be instances where your doctor recommends having the sample taken when fasting, so follow their advice.
What type of diet is best for healthy triglyceride levels?
Since triglycerides are circulating forms of fat, you might think that a high fat diet will raise triglycerides and a low fat diet would lower triglycerides. This is true, but, carbohydrate also has a very important effect on triglycerides. Diets high in carbohydrates, especially sugar, lead to increases in triglycerides as do diets rich in fats.
What drug treatments are recommended for uncontrolled triglyceride levels?
For many people, high levels of triglycerides are caused by disorders such as diabetes, obesity, kidney failure, or alcoholism. Treatment of these reasons for high levels of triglyceride is therefore important. Sometimes high triglycerides are seen together with high levels of cholesterol. When this pattern is seen treatment is directed toward lowering both cholesterol and triglycerides. If diet fails, drug treatment is generally recommended.
Can exercise help with triglyceride levels?
Can I monitor triglyceride levels at home?