Vitamin B12 deficiency anaemia: why investigate absorption?

Already identified vitamin B12 deficiency anaemia is treated differently from iron deficiency. Assessment must clarify the deficiency and its origin: insufficient dietary intake and poor digestive absorption are different situations.

Mean corpuscular volume, or MCV, describes red blood cell size. Larger cells may point towards B12 or folate deficiency, but this measurement does not establish the cause. The doctor chooses additional blood tests according to the circumstances.

Pernicious anaemia, also called Biermer disease, involves impaired absorption of vitamin B12 in the digestive tract. Deficiency may also occur with certain bowel diseases or after stomach surgery. Tell the doctor about these conditions even if your diet seems varied.

A strict, prolonged vegan diet may also be associated with B12 deficiency. Describe the foods you actually eat and any supplements used; this contributes to assessment without establishing a dietary cause on its own.

The form of treatment depends on the identified cause. Ameli describes intramuscular B12 injections for pernicious anaemia and oral forms in certain other situations. Clarify your prescription rather than replacing an injection with a supplement yourself.

For the consultation, gather blood test results and your digestive medical history. Ask what confirms the deficiency, whether poor absorption is suspected and how to organise the chosen treatment. Persistent fatigue or breathlessness warrants medical advice, even before that appointment.