What is a vitamin E (tocopherol) test?

A vitamin E test measures the amount of vitamin E in your blood. Vitamin E (also known as tocopherol or alpha-tocopherol) is a nutrient that is found in every cell of your body. It helps your nerves and muscles work well, prevents blood clots, and boosts your immune system so it can fight off infections from germs.

Vitamin E is a type of antioxidant, which means that it protects cells from damage. But if you have too little or too much vitamin E in your body, it can cause serious health problems.

Most people get the right amount of vitamin E from foods, including vegetable oils, nuts, seeds, avocados, and green, leafy vegetables. Vitamin E is also added to foods such as certain cereals, fruit juices, and margarine. The amount of vitamin E you get from foods doesn't cause harmfully high levels of vitamin E in your body.

High levels usually happen from taking too many vitamin E supplements. Low levels are often caused by digestive diseases, including malabsorption disorders that make it difficult for your body to digest fat. Your body needs fat to absorb vitamin E.

Other names: tocopherol test, alpha-tocopherol test, vitamin E serum test

What is it used for?

A vitamin E test may be used to:

• Find out if you are absorbing enough vitamin E, especially if you have a disorder that affects how your body uses vitamin E.
• Check vitamin E levels in premature babies. Babies born before 37 weeks of pregnancy often lack vitamin E and may develop serious health problems if they aren't treated.
• Find out if you are getting too much vitamin E, especially if you have symptoms and have been taking vitamin E supplements.

Why do I need a vitamin E test?

You may need a vitamin E test if you have symptoms of vitamin E deficiency (low levels of vitamin E) or vitamin E excess (high levels of vitamin E).

Symptoms of a vitamin E deficiency often involve damage to the nerves and muscles. They include:

• Muscle weakness
• Loss of feeling in your arms and legs
• Problems walking and controlling your body movements
• Vision problems

Vitamin E deficiency is very uncommon in healthy people. Most of the time, it's caused by conditions that prevent your body from properly absorbing vitamin E, including:

• Crohn's disease, a chronic (long-lasting) disease that causes inflammation in your digestive tract
• Liver disease
• Cystic fibrosis, a disease of the mucus and sweat glands that's inherited (passed down through families)
• Celiac disease, a chronic digestive and immune disorder that damages your small intestine
• Pancreatitis, inflammation of the pancreas
• Certain genetic disorders, including ataxia with vitamin E deficiency and abetalipoproteinemia (a very uncommon inherited disorder)

Eating an extremely low-fat diet can also lead to a vitamin E deficiency.

Symptoms of too much vitamin E include:

• Diarrhea
• Nausea
• Fatigue
• Muscle weakness

Vitamin E excess is uncommon. It usually happens from taking too many vitamin E supplements. Without treatment, too much vitamin E can increase your risk of bleeding, including bleeding in the brain, called a hemorrhagic stroke.

What happens during a vitamin E test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You will probably need to fast (not eat or drink) for 12-14 hours before the test.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

Normal vitamin E levels vary with age. Your test results should say if your results are normal for your age.

Low vitamin E levels mean you are not getting or absorbing enough vitamin E. Your health care provider will use your medical history and the results from other tests to diagnose the cause. You can usually treat vitamin E deficiency by taking vitamin supplements and treating any conditions that may be blocking absorption.

High vitamin E levels mean you are getting too much vitamin E. If you have been taking vitamin E supplements, you will need to stop. If vitamin E has caused problems with bleeding, your provider may also prescribe medicines to treat you.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a vitamin E test?

Some people believe vitamin E supplements can help prevent certain disorders. But there is no solid evidence that vitamin E has any effect on heart disease, cancer, eye disease, or mental function.

Taking vitamin E supplements may affect how certain medicines work, including certain blood thinners and cancer medicines. It may also affect your body's ability to use other vitamins. So, before taking any dietary supplements, always talk with your provider to find out if they are safe for you.