Did you know that an estimated 10-12 million people in the UK are deficient in Vitamin B12?
And did you know that the most common cause of any deficiency is Pernicious Anaemia? 1
Over the past twenty years, the assay used to evaluate the B12 status of patients has changed and is no longer a reliable indicator of any deficiency. And did you know that the Intrinsic Factor Antibody Test that replaced the more reliable Schilling Test lacks Sensitivity?
The poor performance of these assays was addressed by the British Committee for Standards in Haematology in their Guideline on Cobalamin and Folate Disorders published in 2014 2 and a survey of members of the Pernicious Anaemia Society (PAS) showed that the failings of these assays mean that patients often wait many years for a diagnosis of Pernicious Anaemia – 30% of its members waited five years or more for an accurate diagnosis with 14% waiting over ten years.3
This leads to undiagnosed patients making repeated and futile visits to their GP not only wasting valuable resources but also placing the patient at risk of developing serious and irreversible nerve damage. There are also substantial socio-economic costs involved.
The PAS have successfully applied to NICE for a Guideline on the Diagnosis and Maintenance of Pernicious Anaemia which is currently in development, and they have also formed a Priority Setting Partnership with the James Lind Alliance to identify ten uncertainties relating to the way in which PA is diagnosed and treated.
We would value your input and you are invited to participate in a Survey that will help to identify ten topics that need to be researched to help facilitate prompt diagnosis and more effective and equitable management.
If you would like any further information please see below or contact us by email – firstname.lastname@example.org If you would like to go directly to the survey (which should take just ten minutes to complete) please click here:
The Guideline on Cobalamin and Folate Disorders published by the British Committee for Standards in Haematology makes the following statements:
- ‘The clinical picture is the most important factor in assessing the significance of test results assessing cobalamin status because there is no ‘gold standard’ test to define deficiency’
- ‘In the presence of discordance between the test result and strong clinical features of deficiency, treatment should not be delayed to avoid neurological impairment’
- ‘…patients with strong clinical features of cobalamin deficiency may have serum cobalamin levels that lie within the reference range (false normal cobalamin level)’
- ‘…there is currently no ‘gold standard’ test for the diagnosis of cobalamin deficiency’
- ‘…an elevated mean cell (MCV) is not a specific indicator of cobalamin deficiency’
- ‘The absence of a raised MCV cannot be used to exclude the need for cobalamin testing because neurological impairement occurs with a normal MCV in 25% of cases’
- ‘(the) Serum Cobalamin Assay……..lacks the specificity and sensitivity required of a robust diagnostic test’
- ‘Positive family history or personal autoimmune conditions increase pretest probability of pernicious anaemia’
- ‘All patients with anaemia, neuropathy or glossitis, and suspected of having pernicious anaemia, should be tested for anti-IFAB regardless of cobalamin levels’
- ‘IFAB is positive in 40–60% of cases, i.e., low sensitivity, and the finding of a negative IFAB assay does not therefore rule out pernicious anaemia (hereafter referred to as AbNegPA).’
- ‘Patients found to have a low serum cobalamin level in the absence of anaemia and who do not have food malabsorption or other causes of deficiency, should be tested for IFAB to clarify whether they have an early/latent presentation of pernicious anaemia’
- ‘Patients negative for IFAB, with no other causes of deficiency, may still have pernicious anaemia and should be treated as anti-IFAB-negative pernicious anaemia. Lifelong therapy should be continued in the presence of an objective clinical response’
3. Treating Pernicious Anaemia:
- ‘Maintenance treatment for patients presenting without neurological deficit is with hydroxocobalamin 1000 lg i.m. every 3 months. No further testing for cobalamin levels is required.‘
- ‘…patients presenting with neurological symptoms should receive 1000 lg i.m. on alternate days until there is no further improvement.’
- ‘…the efficacy and cost–effectiveness of oral treatment in wider population-based settings has yet to be established. There are arguments against the use of oral cobalamin in initiation of cobalamin therapy in severely deficient individuals who have poor absorption, especially due to pernicious anaemia.’
4. Complications of Pernicious Anaemia:
Left undiagnosed and untreated Pernicious Anaemia leads to degeneration of the posterior and lateral columns of the spinal cord – Subacute Combined Degeneration of the Cord Secondary to Pernicious Anaemia (also known as Lichtheim’s or Putnam-Dana syndrome).
- NHS Choices Website: https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/causes/ accessed 25/2/21
- Devalia V et al: British Journal of Haematology, 2014, https://doi.org/10.1111/bjh.12959
- Hooper M, Hudson P, McCaddon A, Porter F; British Journal of Nursing, 2014, Vol 23, No 7: DOI: 10.12968/bjon.2014.23.7.376