This is a new NICE guideline on vitamin B12 deficiency , published in March 24. Surprisingly, this is the first guideline that NICE has published on vitamin B12 deficiency. There were some excellent guidelines in 2014 from the British Society of Haematology which I blogged on. Since then (and a pandemic later), treatment has moved much towards oral treatment.
How does this guideline change our practice?
In reality, the majority of the time we are probably already doing most of what is in this guideline. Here are a few of the things that are new or may be a bit different, or that I needed a reminder on.
- We should test people with at least one symptom and at least one risk factor (see below for details of this).
- Remember that vitamin B12 deficiency can present with psychological issues (eg depression, anxiety or psychosis).
- Some medications can affect your vitamin B12. We probably all know about metformin now, but there are others, including colchicine, PPI, H2 receptor antagonists and topiramate.
- Normal B12 testing (ie serum cobalamin) isn’t always the best test. For example, in people that are pregnant, testing Active B12 is much better. I have laid out what NICE says about what to check below. Whether we have access to these tests or not, is another question…
- NICE has given advice on how to manage people with an ‘indeterminate’ result, which is quite helpful.
- Remember that coeliac disease can cause a B12 deficiency and if there is no other obvious cause apparent, then consider testing for it.
- Recreational nitric oxide treatment can also cause a B12 deficiency and normal testing won’t pick this up.
- People of black ethnicity have a higher reference range, so may need treating at a lower level. Bear this in mind when interpreting their results.
- People should be reviewed after 3m of treatment (or after 1m in those pregnant or breastfeeding). Remember that the symptoms can take weeks, or even months to settle. You may need to consider further testing if symptoms aren’t improving or are getting worse.
Who should GPs test for Vit B12?
NICE advises that the following factors are worth remembering in recognising vitamin B12 deficiency.
- Vit B12 deficiency is highly likely after total gastrectomy or complete terminal ileal resection.
- Don’t exclude it if there is no anaemia or no macrocytosis.
- It can present with mental health issues, eg depression, anxiety or psychosis.
