Vitamin B 12 deficiency: NICE guideline summary

### What you need to know Vitamin B12 deficiency is associated with a range of symptoms and signs, resulting in substantial variation in patient presentation . While epidemiological data are limited, cross sectional studies from the UK and US suggest a prevalence of 3% in people aged 20-39, increasing with age up to about 20% in people aged 85 and over.12 Complications of vitamin B12 deficiency include visual changes, paraesthesia, and ataxia. In March 2024, the National Institute for Health and Care Excellence (NICE) published new guidance on the diagnosis and management of B12 deficiency.3 This summary aims to raise awareness of the symptoms and signs, assessment, and management of vitamin B12 deficiency, with particular focus on what is most relevant to general practice and primary care. Readers are directed to the full guideline for a comprehensive review of all recommendations. NICE recommendations are based on systematic reviews of best available evidence and explicit consideration of cost effectiveness. When minimal evidence is available, recommendations are based on the guideline committee's experience and its opinion of what constitutes good practice. Evidence levels for the recommendations are given in italics in square brackets. ### GRADE Working Group grades of evidence