Covid-19 prompted the British Society of Haematology to issue pandemic B12 guidance , and this outlines some of the principles for moving to oral B12 preparations.

This document outlines appropriate referrals to the haematology department.
Who to refer:
Patients:
- with symptoms suggestive of either a spinal cord lesion (subacute combined degeneration or peripheral neuropathy) or visual (optic neuropathy) – same day emergency admission
- not responding haematologically to B12 replacement therapy (where folate and iron stores have been checked and are normal)
- with suspected malabsorption or disease of the terminal ileum should be referred to Gastroenterology
- with neurological symptoms should be discussed with Neurology if advice required.
Who not to refer:
Uncomplicated B12 deficiency
How to refer:
SCI Gateway Haematology at RIE, WGH or SJH.
Primary care investigations
See flow chart on the main welcome page for full detail. Initial tests include:
- FBC and film
- Serum ferritin
- Serum folate
- Reticulocyte count if anaemia or macrocytosis
- Intrinsic factor antibodies (lab will reflexly test if low B12 levels).
Please also see macrocytosis / macrocytic anaemia / cytopenia guidelines, if relevant.
Thanks to the Vegan Society for allowing us to link to their website: https://www.vegansociety.com/resources/nutrition-and-health/nutrients/vitamin-b12
Devalia V et al (2014) Guidelines for the diagnosis and treatment of cobalamin and folate disorders https://onlinelibrary.wiley.com/doi/full/10.1111/bjh.12959 [Accessed 29.11.19]
Linnebank et al (2011) Antiepileptic drugs interact with folate and vitamin B12 serum levels https://onlinelibrary.wiley.com/doi/pdf/10.1002/ana.22229 [Accessed 22.10.19]
Sukumar and Saravanan (2019) Investigating Vitamin B12 deficiency https://www.bmj.com/content/365/bmj.l1865 [Accessed 29.11.19]