Am I just just b12 deficient or PA? So confused what to do next :(

Can anyone help me please, I am so confused as what to do next....

Over the years I have had periods of numbness, pins and needles in my hands and feet, tiredness, mind fog etc which drs tests usually brought down to iron/folate deficiency.

However this time was the worst it's been. In march I started to experience strong numbness and tingling in my left hand to the point it was hard to feel things. I guess I should have went to the doctor then but didn't :(

Coming into April/May my balance was becoming pretty bad but most worrying for me my vision in my right eye was become affected, sort of like colours had lost their vividness (text in books etc were no longer black and crisp, but fat and grey) with what felt like snowy interference. This was accompanied by pain when I moved my eye in different directions. (The pain subsided, but my vision is still affected)

So, finally I went to the doctor who ordered an ophthalmology appointment (which still hasn't come through) - my own optician couldn't see anything wrong.

The blood tests he ordered came back:

B12 156ng/L (191-663)

Serum folate 3.6 ug/L (4.6-18.7)

Serum ferritin 33 ug/L (13-150)

Serum iron level 11.8 umol/L (10-30)

Serum transferrin 4.1g/L (2-3.6)

Percentage iron saturation 11.5% (30-40)

Serum TSH level 2.29 mU/L ( 0.27-4.2)

FBC - not sure what some of these are but though I would include ;)

HB 126g/L (120-170)

Packed cell volume 0.372 (0.36-0.5)

RBCs 4.38 e12/l (3.8-5.5)

MCV 84.9 fl (83-101)

MCH 28.8 pg (27-32)

MCHC 339 g/L (310-350)

Platelet count 235 e9/l (150-400)

WBCs 5.3 e9/l (4-11)

So he noted b12 and folate where low. Said to me that he wouldn't use injections until b12 falls under 100. So packed me on my way with cobalamin tablets 50mcg and folic acid 5mg both to be taken once a day for 2 months til my bloods will be checked again.

He also said iron was slightly low but not enough to be treated.

I said I was worried I wasn't absorbing b12 properly and he ordered intrinsic factor and Parietal cell antibody bloods - these haven't come back yet.

I did a bit of reading around and decided not to take the tablets just yet and get an active b12 test from blue horizon which came back:

Active B12 71 pmol/L (21.5 - 165.0)

So within normal range for them - so does this mean I am absorbing properly and where should i go from here?

I am so upset and confused :( I still haven't taken the medication incase there is any other tests that I could maybe do, and was considering a uMMA test.

Any advice would be much appreciated x

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8 Replies

  • Your B12 is far too low. Even though the active levels look reasonable, you're below range on total B12 and have loads of neurological (nerve-related) symptoms. Nerve damage from low B12 can be irreversible and you don't want to mess around with that. If you can't get injections, then the prescription amount of B12 you've been given is pathetic, and will take forever to raise your levels, and - as I may have already said - you don't want to mess around while nerves continue to get damaged. I would buy the 1000 mcg tablets, preferably labelled as hydroxy or methylcobalamin, because these forms are better utilised by your body.

    Pernicious anaemia (PA) is one of the possible causes of B12 deficiency. If you have PA then you will always need the supplements or injections. If there is a different cause, then you may be alright in future when that cause is addressed. But it makes no difference to the treatment you need today - you're low on b12 and need to top things up, either with some supplements or injections.

    And although your iron stores (ferritin) are okay-ish, ferritin is what's called an "acute phase reactant" which means it can give a false high when you are ill. All the other things on your iron panel point towards iron deficiency. Your serum iron and percentage iron saturation are both low and your transferrin is raised - this is exactly what you would expect to see in someone developing iron deficiency. You don't have anaemia (not enough iron in your red blood cells)... yet, but there's very little iron available to the rest of your body, and that's probably contributing to some of your symptoms! I expect your doctor knows all this, but he seems to be waiting until you actually become anaemic, which is the final stage of iron deficiency - iron in red blood cells is so important that it's the last thing to lose out when iron is short.

  • Thankyou poing for that fantastic informative reply :) I will get on to my doctor and try and get things sorted but not holding out much hope. Sounds defeatist I know, but I am so tired of the incompetence of these professionals who are supposed to be helping

  • Get a new doctor is my first thought. You are deficient in b12 and folate, and you also need iron. You might want to get a vit D test as this is often low as well. You are right not to take the tablets, you should be on injections. You are officially below your reference range. You also have neuro symptoms so need alternate day injections until no further improvement re BNF section 9.1.2.

    Can you see someone else at the practice? Someone who isn't trying to cause you permanent neuro damage?

    The new guidelines may help:

  • Thanks Hampster for your advice :) my parietal antibodies test came back positive , but the intrinsic factor hasn't come back yet as there is a technical problem at the lab. The GP is apparently getting advice from a haematologist on the positive parietal test. So in the mean time I am taking methyl cobalamin and methyl folate but guessing this probably won't help much. Does the parietal result mean I am definitely PA? Or is the intrinsic one more important for that diagnosis?

  • Unfortunately for diagnosis they tend to look at the IFAb test - if that's positive you have PA. However, it only picks up about 50% of cases so if it's negative it means nothing, you could still have PA. This fact has been recognised in the new guidelines I posted above, as they are now recognising "Antibody Negative PA" or "AbNegPA".

    But in my experience of reading other people's stories many doctors decide you don't have PA if the IFAb test is negative. This is when you need to refer them to the guidelines. The other thing clear from the guidelines is that you don't have to have macrocytosis (enlarged red blood cells) to have PA, this is absent in around 25% of cases. And will definitely be absent if you have coexisting iron deficiency (this normalises the MCV).

    Regarding PCAbs I have done quite a lot of reading on this as I am IFAb negative and PCAb positive. PCAbs are found in the vast majority of people with PA (80-90%) but are not considered diagnostic as they are found in some other medical conditions (such as thyroid disease) and also in a small proportion of healthy people. However, if you do any reading about the role of the parietal cells in the stomach you will see that having antibodies against them will lead to PA eventually, and that if you have below range serum B12, raging symptoms, and positive PCAbs then you might as well call it how it is - PA.

    The parietal cells are responsible for producing intrinsic factor and gastric acid, 2 things that are absolutely vital in releasing B12 bound to protein in food and transporting it to the ileum. So if you have PCAbs destroying the parietal cells, you won't be producing as much (if any) intrinsic factor or gastric acid. So the result is autoimmune atrophic gastritis (low stomach acid), and PA. Having low stomach acid also leads to malabsorption of a host of other nutrients - we are rarely just deficient in one thing.

    I've just been reading a book about low stomach acid which explains what's going on in the stomach really well, I can recommend it (particularly if you suffer any gastric symptoms). It's called "Why Stomach Acid Is Good for You: Natural Relief from Heartburn, Indigestion, Reflux and GERD" by Jonathan Wright.

    Sorry, I digress! Wait and see what the IFAb test comes back as, but please bear in mind you still need treatment regardless. And with your neuro symptoms it must be alternate day injections until no further improvement. I mentioned the BNF guidelines, they are summarised here:

    And by the way your doctor should be treating you now, not waiting for the test results, this is quite clear from the new guidelines:

    "Neurological presentation (peripheral neuropathy, sub-acute combined degeneration of the cord) may occur in the absence of haematological changes, and early treatment is essential to avoid permanent neurological disability."

    There is a closed Facebook Group here if you want to join:

    And also lots more info here:

  • Thanks Hampster :)

  • Hi Laurabeebee,

    You will see from the link that hamster supplied that only IF antibody test is 100% conclusive for PA, if positive you have IFAbs positive PA, if you test negative then you are classified as IF Abs negative PA. The IF antibody test is notoriously unreliable, people have tested positive then negative etc.


    "IF antibodies (IFAs), if present, are virtually diagnostic (100% specific) for pernicious anaemia. However IF antibodies have lower sensitivity with studies showing IFAs present in as few as 27% of patients. Therefore the absence of IFAs does not rule out the diagnosis of pernicious anaemia.

    Gastric parietal cell antibodies (PCAs) are less specific but more sensitive for pernicious anaemia. Combining IFA's and GCA's increases the sensitivity to 73% while maintaining 100% specificity for pernicious anaemia.2

    What ever your test results, your treatment should be the same.

    I am (and most of the 7 in my family known to be or were on B12 treatment are) negative for all specific tests for PA, still no doubt we have a problem taking up B12 and am classified as PA (IF negative) but need life long treatment, so do (or did) the others in my family. It is not always known why you are B12 def/ dependent on B12 treatment.

    Kind regards,


  • Thanks for your help Marre :)

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