A vitamin B12 test measures the amount of vitamin B12 in the blood. Vitamin B12 is usually measured at the same time as folic acid because a lack of either one or both can lead to a form of anemia called megaloblastic anemia. Lack of vitamin B12 also affects the nervous system.
- People who have had stomach or intestinal surgery, small intestine problems, or a family history of this anemia as these are risk factors for vitamin B12 anemia.
- Diagnostic purposes - find the cause of certain types of anemia, such as megaloblastic anemia.
- Help determine the cause of dementia or other nervous system symptoms, such as tingling or numbness of the arms or legs (peripheral neuropathy).
- People diagnosed with atrophic gastritis.
For more information on this test, visit labtestsonline.org
Do not eat or drink (other than water) for 10 to 12 hours before the test.