Here is a link to the ‘Guidelines for the diagnosis and treatment of Cobalamin and Folate disorders’, commissioned by the British Committee for Standards in Hematology:

These guidelines contain matters which we think important and which we underpin based on our clinical experiences. Most important are:

  • Vitamin B12 injections i.m. are preferable. Oral suppletion is insufficiently effective with a lot of patients.
  • Apart from the ‘classical Pernicious Anemia’ patients, most patients with sympomatic B12 deficiency have a non-abnormal blood count. They are not anemic, and don’t have elevated MCV. These patients have functional B12 deficiency and benefit from vitamin B12 suppletion i.m.
  • B12 deficiency occurs in all age groups.
  • Since only few clinical trials have been carried out concerning a.o. B12  treatment frequency, evidence based clinical practice, researches and case histories in academic literature offer the main guiding principles for treatment.