Vitamin B12

A vitamin B12 test measures the amount of Reference vitamin B12 Opens New Window in the blood. The body needs this B vitamin to make blood cells and to maintain a healthy Reference nervous system Opens New Window.

Vitamin B12 is found in animal products such as meat, shellfish, milk, cheese, and eggs. Most people who eat animal products are not likely to develop Reference vitamin B12 deficiency anemia Opens New Window unless their bodies can't absorb it from food. Strict vegetarians (vegans) who do not eat animal products and babies of mothers who are strict vegetarians are at increased risk for developing anemia and should take a supplement containing vitamin B12. Vitamin B12 is stored in the liver for a year or more, which reduces a person's risk of anemia.

Vitamin B12 is usually measured at the same time as a Reference folic acid Opens New Window test, because a lack of either one can lead to a form of anemia called Reference megaloblastic anemia Opens New Window. Lack of vitamin B12 also affects the nervous system.

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