Advice on Vit B12 blood test, please

I am getting ready to have the Thyroid Blood Test 10 done by BH but doing a bit of homework first. I have been supplementing with Vit B12 1000 subliminal and also a smallish amount in the B Complex I have been taking. Could you please tell me how long I need to stop supplementing before having the B12 test? I have not taken any for a couple of days and hope to get test done in January. Also is the B12 test included in the thyroid 10 test the Active one that I have read is the best one to have?

Many thanks


22 Replies

  • B12 can hang around in the blood for quite a time and varies from person to person. Maybe ask the question on the PAS forum here on HU.

    What was your level when you started to supplement and when ?

    Details about what is included for the tests should appear on their website.

  • Thanks Marz - I have never had my B12 tested so have no idea what it has been. I did notice though that my hair stopped falling out after supplementing with B12 for a while. I am also on a PPI tablet daily which is also known to lower B12 levels so I started supplementing based on those facts. I will have a look at the PAS site so thanks for that.

  • how are you supplementing B12 ? - if you are swallowing the tablets then the PPI will negate any positive effects.... Also the PPI is a short-term treatment. Have you read the PIL ?

  • Hi Marz - I have been taking Sublingual B12 which is supposed to be more absorb able . I did know that PPI's can deplete the body of Vitamins and minerals. I have to stay on PPI's as I have some damage to my oesphogas (sp) and so the acid needs to be well controlled. In other words I cannot really take the risk of not taking them.

  • You need good acid levels to obtain the B12 from proteins. PPI's prevent the acid being forming in the stomach - which is so crucial for good digestion and the onward journey of B12. I see you have been on this forum since 2011 - and if you check my replies/posts and those of others you will see this topic is discussed many times a week !

    When Hypo the stomach acid is LOW - or when you are older. So - when the acid is low proteins fail to break down in the stomach and hang around as the molecules are too large to pass into the duodenum. Hence there is fermentation and the upward movement into the oesophagus of fermenting foods can cause GERD or acid reflux. Think of home made beer in a bell jar with the yeast bubbling upwards :-)

    Docs are well paid for prescribing PPI's - and if you are Hypo then it is possible when you are optimally treated your low acid will improve. They are paid less for Thyroid treatments..... I have the list of a few years back !!

    Your PIL in the box of tablets will tell you that they are designed as a short course of 8 weeks. They are addictive. Docs easily pull out the prescription pad as going the natural route takes too much time and knowledge.

    I would try to wean off the PPI's and find alternative treatments which are well documented here in various posts. Type GERD or Acid Reflux into the Search HealthUnlocked on the Green Bar at the top of the page and have a read. There are over 200 posts on PPI's alone - just looked !

  • Thanks Marz - i will have a read when i get a mo. I just have to be extremely careful with my problem so it is always choosing the lesser of 2 evils I am afraid. I want to get my thyroid tests out of the way first and see where I am with that.

  • The B12 test in the Thyroid + 10 is not the active one - they do that test on its own. I'm going to have mine done in the New Year and I stopped supplementing over a month ago.

  • Thanks Trixie - I do want the thyroid 10 test - will I still get a good picture of what the B12 levels are like though even though it is not the active one. Cannot afford to have loads of different tests at the moment.

  • The Active B12 Tests informs what is happening at a cellular level - where the B12 is needed. The regular blood test is not 100% reliable as it is a snapshot of that particular moment. It is however a diagnostic guide. Only 20% of the blood result is available to be transported and utilised in the cells. There is both bound and unbound B12 in the blood.

    Google Active B12 Testing and the website will appear. I think it is St Thomas's in London.

  • Thanks again Marz - I may well get the Active one done with BH later on if the other B12 test comes back with a lowish level result. I am going to get the Thyroid 10 test done and the B12 is one of the tests thrown in within the ten.

    You have been a great help - lots of bedtime reading for me!

  • You do not have to abstain from taking B12 when having the Active Test. Having spoken with Martyn Hooper - Chairman of the PAS - he informed me that it can take literally months for B12 to clear the system - so any tests will be skewed. You need a result of around 1000.

  • Would that result of around a 1000 apply to the other B12 test too?

  • The 1000 is a level suggested by Sally Pachlok in her book Could it be B12 ? - in order to prevent cognitive decline. Anything under 500 can be the cause of neurological degeneration. These levels refer to the Serum B12 test and not the Active Test.

    I do not know much about the Active Test - you could look in the Search Box on the Green Bar above and press Enter on your keyboard. I live in Crete and am able to buy B12 injections over the counter without a prescription for a couple of euro. I have weekly injections due to lack of B12 diagnosis and the correct information some 42 years ago :-(

    The link above takes you to an earlier post of mine !

  • Thanks so much Marz - for sure we seem to have to be our own advocates when it comes to health don't we.

    Will have a look at your link - lucky you in Crete - the weather over here is just rain and more rain .


    The above link is from the main website of Thyroid UK - and explains about PPI's affecting Levo uptake :-(

    Yes you are right we have to be our own advocates ! You can check out my journey to wellness by clicking onto my name to read my edited profile !

  • okay - thanks I will - good to hear a success story on here. So many people looking for answers - something failing in the NHS system somewhere.


    Scroll down for the video - which I think explains very well what is wrong with the NHS.....

  • I remember when this was on TV (Doctor in the House). What a lovely GP he sounds - I cannot see the NHS taking this on board though at least for not some years. I have always thought that if GP's should start off their diagnosis methods with blood-testing the obvious first - such as B12, Vit D iron folate etc especially in an older person. Instead they always want to go for the sledgehammer effect and chuck us on meds that the drug companies make nice fat profits from. I reckon they would save money by eliminating the obvious first. Most complicated problems lie in simple answers - it is just finding them.

    I read your profile and my what a tough time you have had and so good to hear that you have come through all of that. How did you keep your spirits up? I have had a toughish year with losing my dearly loved brother suddenly and also husband having open heart surgery straight after my brother died. I think it is all catching up with me now,

    Take care and thanks for your insight


    I have saved up and bought this book ! Research papers from around the world - brought together by an Endocrinologist and a Cardiologist for the first time I believe. T3 is the Star of the Show - Liothyronine is the name the use for T3 . You can click onto the book and read the contents and more.

    |Heart issues are systemic and not just within the heart.... I find all the connections fascinating....

    Sorry to read of your difficult times - just take good care of yourself. I have always been a positive person - having grown up on a farm where cows needed milking twice a day whatever the state of health prevailed !! My poor Dad - he worked so hard - but sang his heart out when ever the opportunity arose - played his banjo-ukulele - recited the Lion and Albert perfectly - danced well enough to go on Strictly - and had my amazing Mum at his side with endless ideas. I could write a book about them....

  • I will have a read of that on Amazon - it looks interesting.

    That generation could teach a thing or two to this generation couldn't they. I miss my parents too as both dead now.

    Yes a very trying year for me - that is what I am trying to sort out now - whether these symptoms I have is to do with the thyroid (under/over) or whether it is all down to anxiety. The symptoms seem to be roughly the same.

    Thanks for listening anyway and you take good care of yourself too. Good folks are hard to come by!

  • Go with sorting the thyroid along with the B12 - etc.... It all made such a difference for me.


  • I am going to ring BH next week and get all the tests done - just need to decide whether to try finger prick or find someone to take the blood from the arm for me.

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