In a retrospective study with existing values of vitamin B12 and holotranscobalamin 4 strategies are simulated and the results and costs are compared.

Generally, cobalamin ist substituted by intramuscular administration. However, oral preparations are also available. Aims of the focus groups are to investigate the awareness of a (potential) deficiency and to identify a therapy for best adherence.

Various diagnostic strategies exist for the identification of a cobalamin deficiency. In a retrospective study with existing serum values of vitamin B12 and holotranscobalamin 4 strategies are simulated and the results and costs are compared.

A cobalamin deficiency can have various causes: Dietary habits (vegetarian, vegan), advanced age, pernicious anaemia, gastrectomy, drug interactions (metformin, proton pump blocker). Therapy is often performed by intramuscular administration of cobalamin. However, oral preparations are also available in very different dosages. Investigators want to investigate with focus groups whether different patient groups are aware of a (potential) deficiency, how cobalamin is actually substituted (with registered or otherwise acquired products) and which therapy would lead to best adherence.

Inclusion Criteria:

• potential cobalamin deficiency

Exclusion Criteria:

• refusal to take part in a survey

potential cobalamin deficiency