Vitamin B12
A blood test that measures how much vitamin B12 is in your blood.
Vitamin B12
A blood test that measures how much vitamin B12 is in your blood.
Also known as
- Cobalamin
What it measures
- Vitamin B12 level
Why a doctor may order it
Most often done when other blood tests suggest a type of anaemia called megaloblastic anaemia. A provider may also suggest it if you have certain nervous-system symptoms.
What it helps evaluate
It can help a doctor find out whether low vitamin B12 could explain certain kinds of anaemia or nerve symptoms.
Preparation
Certain medicines may affect the result, so your provider will tell you if you need to stop any. Don't stop a medicine unless told to.
Fasting
MedlinePlus says you should not eat or drink for about 6 to 8 hours before this test. Your lab will confirm.
Important considerations
- Only a doctor can say what a low or high result means for you.
Discuss results with your doctor
Talk to a doctor about your symptoms and about what your results mean — a single result is not a diagnosis. See a doctor promptly for severe or worsening symptoms.