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Vitamin B12 test

2-minute read

Vitamin B12 is vital for making red blood cells and for cell and tissue repair. Vitamin B12 is also needed for nerve health.

Vitamin B12 come from food such as meat, poultry, seafood, milk, cheese and eggs.

What is being tested?

This test measures the amount of vitamin B12 in the blood. Folate is usually tested at the same time.

Why would I need this test?

Your doctor might request this test:

  • if you have anaemia (lack of red blood cells) or an abnormal blood test
  • if you have symptoms of neuropathy (tingling or numbness in the hands and feet)
  • to help check your nutritional status, especially if you are a vegan
  • to help diagnose the cause of changes in your mental state or behaviour

How to prepare for this test

You may need to fast for 6 to 8 hours before your blood sample is taken.

Understanding your results

A lower than normal level of vitamin B12 means your body lacks the vitamin. However, the result does not provide information about what is causing the deficiency or how severe that condition is.

Vitamin B12 deficiency can be caused by a wide range of conditions. It can also be caused by a vegetarian or vegan diet. You need to discuss your results with your doctor to fully understand what the results mean for you.

More information

About vitamin B12 testing

Pathology Tests Explained has more information about vitamin B12 testing.

About blood testing

Visit healthdirect's 'Guide to blood testing' to learn more about blood tests in general, including information about:

  • what to consider before having the test
  • what happens during a blood test
  • results accuracy
  • blood tests cost

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: August 2020

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