I was advised by someone over on the thyroid community to post my Vitamin b12 blood test results here for advice.
I had a rest with Thriva while testing my thyroid and based on those results my GP tested me again on the NHS. He now tells me my levels are normal, but the input from the thyroid community expresses concern about deficiency and possibility of pernicious anemia.
Any thoughts and advice would be most welcome.
19/05/2021 Thriva result Active B12 - 31 pool/L (37.5-188)
19/07/2021 NHS result. Serum Vit B12 - 204 ng/L (130-900)
Thank you in advance.
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Written by
Allyfin1
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Interpreting serum B12 is very difficult. a) The test is only accurate to 20% and
b) the normal range is enormous. People tend to sit at a particular point in the range and maintain levels using stores of B12 in their liver. However, if you have a B12 absorption problem then this release mechanism is also affected and levels start to plummet.
This means that people can be deficient well into the normal range and in terms of detecting a B12 deficiency the serum B12 test is extremely difficult to interpret as a single point test.
If the tests you had done were from kits then the GP may have concerns about the conditions in which the sample was taken and hence the accuracy of the results.
Did you have an earlier test done - eg when your thyroid condition was diagnosed - and did that show a much higher B12 level?
Because of the problems with using serum B12, guidelines tend to stress the importance of symptoms in evaluating a potential B12 deficiency - though the overlap with thryoid problems may make this difficult unless your thyroid is well controlled.
There are a number of ways that thyroid problems can link to B12 absorption problems, particularly if your thyroid problem is auto-immune.
Sorry this isn't giving you a clear cut answer.
Suggest you write to your GP outlining your symptoms and the problems with interpreting the serum B12 test and listing your symptoms.
Reference these guidelines produced by the BCSH as supporting information on the limitations of the serum B12 test and also for the protocol on identifying causes of deficiency that they contain.
From personal experience I can tell you it is possible to have severe B12 deficiency with an in range serum B12 result.
UK guidelines suggest that a person who has the symptoms of B12 deficiency should be treated even if serum B12 is within range to prevent neurological damage.
Each CCG/Health Board in UK will have its own local guidelines on treatment/diagnosis of B12 deficiency. I recommend you track down the local guidelines for your CCG/Health Board and compare them with BSH, BNF and NICE CKS links above.
Search forum posts for "local guidelines" as some have been posted on forum or try an internet search or submit a FOI (Freedom of Information) request to CCG/Health Board asking for a copy of local B12 deficiency guidelines.
Good to know what you are up against locally as some local guidelines differ significantly from BSH, BNF, NICE CKS guidance.
Hope you are not in the UK area discussed in blog post below which has a poor reputation on this forum for treatment of B12 deficiency.
I'm sorry that you are having so many symptoms. As Gambit62 says, there are considerable overlaps between B12 and thyroid, particularly as you have an autoimmune thyroid issue, and as you don't have a GP taking much notice of either you are going to be struggling. Unfortunately now that you have started a B12 supplement, testing becomes more problematic. Getting your vitamin D to a better level, considering an anti-inflammatory diet (if possible test for Coeliac before going gluten free), and seeing how your symptoms react by keeping a diary now you are on the B12 may be all you can do for the moment. Getting hold of copies of any old results could be enlightening. Best wishes
The Thriva one that is testing just your active B12 ( B12 that is bound to transcobalamin) which is called the HoloTC (or holotranscobalamin) test. This has been returned as below range.
The NHS one - a serum B12 test which tests total B12 (active and inactive). So B12 that is bound to transcobalamin (active) and B12 that is bound to haptocorrin (inactive). This has been returned as within range.
Because of the inaccuracy of testing, and because you are left trying to make sense of two different testing methods from two different sources, your GP might be persuaded to look into this further. If your concerns are based on worrying symptoms despite a well-managed thyroid condition, for example, or if your family history would suggest PA as a possible cause.
GP monitoring direction of travel would be useful - B12 could be on it's way downhill- but why wait for that if there are other warning signs ?
While you are asking, if not done recently, ask for folate, ferritin and vitamin D to be checked. I'd usually say thyroid as well, but that's been covered already.
I would add that 130 ng/L as a "normal range" starting point is quite mean.
My own initial test result was not much lower than your's at 196 ng/L , but I was lucky enough to have a local range starting point of 197 ng/L - and a very good GP.
Links below are to threads where I left some detailed replies with lots of B12 info which you may find useful eg B12 deficiency symptoms lists, causes of B12 deficiency, UK B12 documents, causes of b12 deficiency, B12 books, B12 websites, B12 articles and a few hints on dealing with unhelpful GPs.
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