Tests needed for daughter already supplementing with injectable b12

Daughter has been on b12 jabs for over 3 years; still unwell with neuro symptoms, and b12 level of 2000. So, going to doctor to ask for more tests to determine why level is so high when she's obviously showing many symptoms of deficiency, (3 of my daughters are b12 deficient). Know about functional deficiency etc, but could someone tell me what other test are worth asking that won't be a waste of time as she is on the jabs 7 weekly. I've read about many tests - MMA, Homocysteine, Active b12, TC11, Thyroid, Folate, Ferritin, Vit D, etc, but which ones will be ok with this supplementing, and are there any more, and which 'forms' of the tests should they be? Thank you.

10 Replies

  • TC11 looks at whether you have the anti-bodies that are cause functional B12 deficiency.

    MMA, Homocysteine and Active B12 would require stopping supplementation for a few months.

    Thyroid etc aren't directly related to B12 (though folate is needed to process B9 so is a good one to look at) so I don't think they should be affected by the supplementation but I am not an expert - far from it.

  • Thanks...I don't think we'll stop the jabs for a few months though as she is unwell enough, but I am going to speak to the doctor about TC11 antibodies and functional b12. Will see how it goes.

  • If you don't mind me asking where does your daughter get her injections from?

  • From the doctor at the moment.

  • Hi,

    Have you looked at the possibility of there being an MHTFR gene mutation in your family?


    Its probably unlikely that NHS will test for this but if you google "UK private tests MTHFR" there are places in UK you can have it done.

    Have you rung the PAS Head office: 01656 769 717

    They may be able to make suggestions. Some sufferers have infusions of B12.

  • It certainly seems strange that three out of five daughters have a b12 problem. I have seen this MTHFR spoken about before, and it's certainly worth a look at. I'll mention it to the doctor when we go to see him...nothing ventured etc...Thanks for the PAS number. What do you mean by infusions of B12? Neither my husband or I have any symptoms of b12 deficiency..although I'm keeping my eye on him as he's been on PPI medication for several years now.

  • Another inherited cause of B12 deficiency:


    Mutations of the gastric intrinsic factor gene.

  • Is there a comprehensive test available in the UK that covers things like MTHFR and GIF mutations?

  • I have not specifically checked 23andme to see what MTHFR and GIF mutations are included - but did upload my 23andme results to:


  • Hi,

    B12 infusions are where you are put on a drip that contains B12. The PAS may be able to tell you where you can find someone who will do this.

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