When should I consider referring a patient with vitamin B12 deficiency for further investigation or specialist management?

Refer a patient with vitamin B12 deficiency for further investigation or specialist management if they have neurological involvement, such as neurological or mobility problems related to peripheral neuropathy or central nervous system disease, including myelopathy, or if they have symptoms suggestive of neurological damage, as this requires urgent specialist advice from a neurologist and/or haematologist ⁴.

Consider referral if the deficiency is suspected to be caused by autoimmune gastritis or if there is a risk of gastric cancer, especially in cases of autoimmune gastritis or if new or worsening upper gastrointestinal symptoms develop, warranting referral for gastrointestinal endoscopy ⁴.

Additionally, if vitamin B12 deficiency is suspected to be due to a poor diet and dietary causes are confirmed or suspected, referral to a dietician may be appropriate ¹,²,³.