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Pernicious Anaemia Society
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Advice please on latest B12 result and what to do next about possible B12 diagnosis

Hi Everyone,

Hope you are all having a good weekend. I took everyone's advice on here and did a detailed letter to the GP about my diagnosis of B12 deficiency and lots of examples on why my B12 result could be coming back in lower range, problems with the IF test and why I'm showing no macrocytic anaemia maybe because of iron deficiency anaemia.

I sent the letter to the GP and had a phonecall back to say they would be discussing my case at their next GP meeting. I was a little bit hopeful after that.

Now this morning Iv'e had a letter from the neurologist saying my recent B12 test was

874 ng/l 197 - 771. I really don't understand why it is so high as I have stopped all supplements at the moment. The intrinsic factor was negative again. She says of course this goes against a diagnosis of PA. She did agree to an MRI of the spine which is next week.

I'm really disappointed with this as I was planning on getting an Active B12 and MMA test to see if I could clarify anything but seems no point when my B12 is showing that high.

I'm doubting myself again now. I do have a Thyroid issue too and it seems this condition has similar symptoms. My neurological symptoms are brisk reflexes, cognitive decline, left upper limb dyspraxia occasional tingling in feet. My walking is affected now and I trip it is like foot drop I think and feel dizzy and lightheaded.

The only other diagnosis mentioned to me was Fibromyalgia so far which I don't agree with. I think this neurologists letter is probably going to affect the GP decision.

Could anyone please give me advice or thoughts please.

11 Replies

how long had you stopped supplementing? recommended period before a test is at least 3 months

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Hi Gambit62 ,

I had my last loading injection on 10th April and have not taken any extra B12 since then. I know the serum result is unreliable but just wondering if Active B12 and MMA would be pointless now. Don't think this neurologist letter is going to help now either.

Just wondering if I should give up on a diagnosis and start self treating. Some of my symptoms improved after the loading injections but have all returned now so I'm worried.


After loading shots normal range doesn't apply. Even 6 months afterwards the results of both serum B12 and active B12 can be affected.

High levels of B12 can cause a reaction in some people that stops B12 passing from blood to cells where it is used. Although it sounds counter-intuitive the best way of treating this seems to be to keep levels very high - presumably this means there is enough in the blood to beat the reaction so enough trickles through to cells.

From what I have read it would appear that this reaction also results in B12 being retained in the blood for longer.

If it is the case that you have had this reaction in response to the loading does then MMA could be raised so it might still be a useful test - and think the understanding is that it would be raised but as different people present with different B12 issues in different orders this might not apply.

You could try pointing your GP at the area of the PAS website specifically geared towards medical professionals


and you could also try sharing this article.


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Hi Gambit62 ,

Thank you for your reply. Would you know say if I did the Active B12 test and it came back normal which seems likely now and the MMA was raised would that be enough for a diagnosis. I just wouldn't want to use money that would be a struggle for me anyway if the GP is just going to dismiss it.

I have had an awful time with this GP practice since March. I have recently sent them a detailed letter with the BSH guidelines, BMJ article PAS symptom list and the update for health professionals from the PAS site. I just feel if they don't take notice of all this there is not much hope and also this neurology letter is not going to help.

Don't know if I would be better self treating now and forget about getting doctors help as it is causing me a lot of stress.

Any further advice would be much appreciated and thanks for your replies so far. I will read the article myself but sadly the GP's seem to dismiss info I give them.

Also I had a B12 result in July of 371pmol 140. - 724. And now it's over the range.


I wouldn't be inclined to think that forking out on MMA probably isn't the best use of limited financial resources.

Are you saying that your B12 levels have risen between July and whenever the latest results were without any supplementation in the meantime?

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Hi Gambit62,

Yes I think your right and the tests I was considering are not worth it now. Yes I had a private test done in July mainly for my Thyroid but I included the B12.

This latest result is from just over 3 weeks ago and no I deliberately have been avoiding B12 supplements because I was trying to get a diagnosis.

Only thing that is different is I've now started Thyroid medication. Maybe these neurological symptoms are to do with the Thyroid just my symptoms fit better with a B12 deficiency and also don't think they are improving on Thyroid meds and they did seem better after the B12 in April.

I'm confused about this rise in levels really


did you supplement biotin (B7) at all - apparently that can produce false high readings in tests for B12 and tests for thyroid.



Hi Gambit,

No I don't use Biotin. Only supplements have been vitiamin D3, K2 MK7, Vitamin C and iron occasionally.

Just wondering could there test machine be a really old one they still use the ng/l compared to the pmol in the private test.


genuinely are different ways of measuring in different labs - not kit specific so not not going to be old fashioned equipment.

if it was private and you were providing the sample yourself then that does introduce another possible source of error/difference.

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I'm reluctant to suggest this in many ways but I'm wondering if you've checked the symptoms list for hyperparathyroidism? So many symptoms of these conditions can overlap which makes it difficult to pin the tail on the correct donkey. There are several UK organisations but this is recommended for general reading:


If you've got access to your online records then it might be practical for you to rule this out really quickly by checking for any blood test results you've had for calcium, phosphate, vitamin D, and the parathyroid hormone.


I know nothing about this other than what I've gleaned from various acquaintances being assessed for it.


Thank you ITYFIALMCTT for your reply. I'm glad you have made a suggestion as I would like to find out what's wrong and am open to suggestions.

I read the symptoms in the link and yes a lot of them are similar but I always seem to have low blood pressure. Also looking at my blood tests calcium is always in the middle of the range (normal), Phosphate also normal on last test. Vitamin D was very low in March but I have started supplementing so that is higher now. Have never had the Parathyroid hormone done but if calcium is normal maybe seems unlikely.

Thank you for reply anyway it helps to think of everything it could be.

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