Referral criteria from primary care - vitamin B12 deficiency

Seek urgent advice from a haematologist if:

• the patient is pregnant
• if functional B12 deficiency is suspected i.e. strong clinical features of B12 deficiency, e.g. megaloblastic anaemia or subacute combined degeneration of the cord, despite normal vitamin B12 (1)
• if pancytopenia then seek urgent advice from a haematologist (2)
• haematological malignancy or other blood disorder is suspected - refer urgently using a suspected cancer pathway referral

Non urgent haematology referral/seeking expert haematologist advice:

• following investigations the cause of vitamin B12 or folate deficiency is unclear or uncertain (2)
• non-response to vitamin B12 treatment.
• mean cell volume is persistently greater than 105 femtolitres (4)

Consider seeking urgent advice from a neurologist if:

• neurological symptoms are present

Refer to a gastroenterologist if:

• malabsorption is suspected or if there is a suspicion of gastric cancer or coeliac disease
• gastroscopy is recommended initially in patients diagnosed with pernicious anaemia for the diagnosis of atrophic gastritis and for evaluation of gastric malignancies (3)
  • if pernicious anaemia and gastrointestinal symptoms - particularly if there is a suspicion of gastric cancer (for example co-existing iron deficiency)
    • if there is a suspicion of gastric cancer then refer urgently using a suspected cancer pathway referral

Consider referral to a dietician if B12 deficiency is due to poor diet.

Reference:

1. NHS Wiltshire CCG. Investigation and treatment of Vitamin B12 (cobalamin) deficiency in primary care.
2. Royal United Hospital Bath NHS Trust. Guidelines for the Investigation & Management of vitamin B12 deficiency.
3. Mohamed M, Thio J, Thomas RS, Phillips J. Pernicious anaemia. BMJ. 2020 Apr 24;369:m1319. doi: 10.1136/bmj.m1319. PMID: 32332011.
4. NICE. Vitamin B12 deficiency in over 16s: diagnosis and management. NICE guideline NG239. Published March 2024.