Confused about high B12

Hi I'm a bit confused went back to see the doctor about still not feeling well after having my B12 inections six weeks ago, he sends me for another blood test this comes back saying that my thyroid (I have an underactive thyroid for the last 17 years) came back at 17.16 which is really high as it was 0.8 six weeks ago and my B12 which was 178 six weeks ago has shot up to 1500 too high now can't seem to get it right, would like to know if this has happened yo anyone else and what it means thanks x

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  • I'd say that you can relax about the B12 level as a B12 level of 1500 cannot be described as too high as B12 is completely harmless and non-toxic. The injections do not aim to get the B12 to any specific level, just to get much needed B12 into you at an adequate level. It is not surprising anyway that the B12 was at this level as the test was between injections. B12 levels should be checked just before any injection, not after, as the injection will raise the levels.

    You say "B12 injections" - does this mean that you were having a course of loading doses?

    Judging by the relationship of the figures you quote for the thyroid test this must be the TSH you refer to. Your doctor should really be investigating why your TSH has suddenly shot up after seemingly being stable at around 0.8. By the sound of your question he did not test the FT4 and FT3, if he did it would be useful to put all the levels and ref. ranges here and there are plenty of people who will be able to help you understand what is going on.

    Please remember you can ask to be referred to an endocrinologist.

  • Thank you for your answer I have had a course of six B12 injections and the only reason they checked my levels after is because I am still feeling really tired so they gave me another battery of tests and that's when they found that my TSH level had gone up so much they are retesting my levels again in 3 weeks as tthey put it up from 125mcg to 150mcg and then she said something about seeing an endocrinologist. I'm sure they are trying to brush me off but t could be wrong

  • Thank you for your answer, I have had a course of six injections of B12 and the only reason they checked my levels after is because I am still feeling really tired so they gave me another battery of tests and that's when they found that my tsh levels had gone up so much, they are retesting my levels again in 3 weeks as they put my thyroxine up from 125mcg up to 150mcg and then she said something about seeing an endocrinologist. To me they seem to be trying to brush me off but I could be wrong.

  • You will not be absorbing all of your B12 injections. There are research papers that say you will only absorb UP to 25% of an injection at any one time. Have you looked at the Pernicious Anaemia society? We try to help as much as possible on there and the forum is a mine of information. Many people need their injections much sooner than the standard 3 months and when taking into account the minimum that you absorb from the injection, this makes sense. I myself am still injecting several times a week some 2 years later and cannot cut back on this.

    Have you had your folate checked? Manu people are low in folate. You need folate to enable the B12 to be matabolised and preferably need to be in the upper end of the range to feel any benefit. I take 5 mg each day, I have a high need for folate.

    Lastly, I have heard many people with hypothyroidism say that once they start their B12 injections they do not need as much thyroxine, in actual fact their meds are cut down as B12 enables thyroxine to work more efficiently. Most Dr's will not accept this but it is down to how you feel that matters. Obviously you would need to discuss this with your Dr. Having a look at the PA site if you haven't done so already will help answer any further questions that you may have regarding thyroid/B12.

    Good luck!

  • Thanks for answering still can't understand if that is the case then why has my tsh levels gone up instead of down. Apparently my folate levels are ok but I have no faith in drs as I seem to be going round in circles and getting frustrated by it all I wish people would just tell me in laymans terms what effect all this is having on me but mostly my body.

  • It really good that an endocrinologist has been mentioned already, You don't have to worry about being brushed off, sounds as though you are lucky!

    Please make sure you get copies of all blood tests, it is your right, as you may know already.

    If you want to have a look in the British National Formulary re your B12 then you can consult it online:

    bnf.org

    Just sign in as instructed and you can half an hour on the site to read and print out. Go to section 9.1.2 Drugs used in megaloblastic anaemias.

    Under HYDROXOCOBALAMIN you can read of the differing treatments for pernicious anaemia without neurological involvement, and PA with NI.

    Not that I do not trust doctors.....it's good to know...knowledge is power.

  • Thanks I will look on that and hopefully give me some more info on this condition.

    As you say "Knowledge is power"

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