A vitamin B12 test measures the amount of vitamin B12 in the
blood. The body needs this B vitamin to make blood cells and to
maintain a healthy nervous system. 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
vitamin B12 deficiency anemia 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
folic acid test, because a lack of either one can lead to a form
of anemia called megaloblastic anemia. Lack of vitamin B12 also
affects the nervous system. Why It Is Done A vitamin B12 test is
used to: - Check for vitamin B12 deficiency anemia. There are
several risk factors for