Pernicious Anaemia: symptoms, diagnosis, Vitamin B12, ME/CFS and the NICE guideline review | 16 February 2018

February 16, 2018


A recent blog by Martyn Hooper, Chair of the Pernicious Anaemia Society, was brought to our attention.

Martyn had attended the NICE stakeholder workshop last month, that initiated the guideline review for ME/CFS.

Similar Symptoms

Martyn's interest lies in the overlap in symptom presentation between Pernicious Anaemia (PA) and M.E. and the lack of routine testing in the current NICE guideline for ME/CFS:

“The symptoms of the disease are incredibly similar to those of Pernicious Anaemia – extreme and constant tiredness, difficulty thinking straight, mood swings etc. etc.


“And I know that a great many members of the Pernicious Anaemia Society were suspected of having ME and diagnosed with the condition before finally being told that they had Pernicious Anaemia.


“I suspect that a great many people who have been diagnosed as having ME/CFS actually have Pernicious Anaemia; and the reason I say this is because the current NICE Guideline states that no investigation for any B12 Deficiency should take place unless there was signs of macrocytosis from the full blood count taken.” 


Martyn went on to say that his suggestion that the new guideline recommend that testing take place as part of the diagnostic process for M.E. was well received and taken on board.

This could mean that more people are more appropriately diagnosed – and treated – even though testing of B12 in the blood is not completely reliable (see Martyn's blog).

What is pernicious anaemia?

Pernicious anaemia (PA) is the most common cause of B12 deficiency in the UK.

It is an autoimmune condition that causes the body's immune system to attack cells in the stomach, limiting their ability to absorb B12. PA is generally treated with regular B12 injections.

For more information, see NHS Choices or the Pernicious Anemia Society.

Vitamin B12 and M.E.

Dr Shepherd, Hon. Medical Adviser, to the ME Association has talked previously with Martyn, and recognises the importance of excluding PA before a diagnosis of M.E. is made, and any treatment of M.E. with vitamin B12 is considered.

The ME Association has produced a leaflet that covers all aspects of vitamin B12 – causes of B12 deficiency, symptoms, blood tests, treatment, research into the possible link to M.E.

This leaflet can be downloaded or ordered from our online shop.

Summary of the key points:

  • Although some people with M.E. report that vitamin B12 injections have been helpful, there is no robust scientific evidence to currently demonstrate that vitamin B12 deficiency occurs in M.E.
  • There are no results from clinical trials to indicate that vitamin B12 injections are a safe and effective form of treatment in M.E.
  • If people are going to take vitamin B12 it is very important to make sure that Pernicious Anaemia (PA) has first been excluded. PA is an autoimmune condition that results in decreased absorption of B12 from the gut – hence the need for injections.
  • Excluding PA is important because it can cause very serious neurological complications (i.e. sub-acute combined degeneration of the spinal cord ( if not properly treated.

The ME Association Ramsay Research Fund is keen to investigate the possible role of vitamin B12 in ME/CFS, and we have had some preliminary discussions regarding a small clinical trial.

Finally, it is worth noting that vitamin supplements are not recommended in the current NICE guideline for ME/CFS. Therefore, most doctors are going to be reluctant to prescribe injections to people with M.E. – unless there are sound reasons for doing so. What NICE currently regard as inappropriate prescribing of vitamin B12 can also lead to a GMC investigation and ban.

Image copyright: kerenby / 123RF Stock Photo

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