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Pernicious Anaemia Society
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Blood Test Advice please


So I got my private intrinsic factor antibodies test results back today (in case anyone has not read my previous results, I decided to go down this route after waiting since November for ones ordered by my GP - not his fault, think it's the lab being funny for some reason). Came back as negative but the comments from the consultant (as has been described on here before too) were: "Intrinsic factor antibodies are highly specific for pernicious anaemia (PPV of 95%) but have a low sensitivity (40-60%), the absence of intrinsic facto antibodies does not exclude a diagnosis of PA."

So basically, bit frustrating (back to square one I feel, but I know it can be notoriously hard work to get a clear diagnosis), but I wanted to ask, if I was to investigate further down the private route, what tests should I be asking for - I know about the parietal cell antibodies one (it's quite expensive!) but are there any others I should be looking at too?

I've had loads of blood tests done over the years showing low B12 (although sometimes borderline low - not 'low' by NHS standards, say like 200-300, after injections), and I know from the time when they agreed to treat me for life (supposedly!), there are different ones because it was a neurologist who told me there are different tests, after he asked me if I'd been tested and it had come back ok from the one my GP did at the time. Currently, my GP has been looking at my levels from when I've just had my injection to when it's due and it's going from something like 2000 to 300.

Also, has anybody got any experience of sharing these private results with their GP? Obviously I'd like my medical records to be as conclusive as possible but I'm just a bit scared because it says negative and I don't want to be taken off the 3 monthly injections I'm currently receiving (took me long enough for them to commit to that and I suffered some neurological damage in the process).

Help and advice much appreciated. xx

10 Replies

Hi Nuala88 I don't know if this will help....

False normal B12 results and the risk of neurological damage

(U.K. N.E.Q.A.S Haematics.org.uk)

In the event of any discordance between clinical findings of B12 deficiency and a normal B12 laboratory result, then treatment should not be delayed. Clinical findings might include possible pernicious anaemia or neuropathy including subacute combined degeneration of the cord. We recommend storing serum for further analysis including MMA, or holotranscobalamin and intrinsic factor antibody analysis, and treating the patient immediately with parenteral B12 treatment.”

Best regards,

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Personally, I've decided not to get an anti-IF test, just in case it came back negative and some eejit decided that it was a good excuse to stop treatment. So I would just forget about this result and never mention it to my GP.

If your treatment regimen is working, I'd be happy at that.


Thanks clivealive and fbirder

Just got another questions as well - I've just heard back from Blue Horizon who did the intrinsic factor test as I'd asked them if they do a parietal cells antibody test as I couldn't find it on the website I was using and they've said it's part of the Auto Antibody Profile (include Gastric Parietal Cell Antibodies test) - it's a bit cheaper than I thought too so win there. Question is, has anyone had this, and also, does having a recent B12 injection affect it - only asking cause I've got mine tomorrow so might have to wait a bit if it does (I did this with the intrinsic factor one as I think I read somewhere that it can affect results - had test on 1st Feb, last injection was 16th November).


GPCA test is no longer recommended in the UK as a test for diagnosing B12 PA because it just isn't very accurate - both ways. Personally I wouldn't waste money on it.

You obviously have an absorption problem - you could try going down the route of rulling out others eg coeliacs and crohn's - though with either of those I'd expect to find multiple deficiency and absorption problems.

Or you could just go on repeating the IFA test until it comes back positive.



Have you ever looked into MTHFR gene tests?

If they try to take you off the 3 monthly injections, perhaps you could show them the BSH Cobalamin and Folate deficiency flowchart below.


Makes it clear in UK that a person with low b12 with a negative result in IFA test, who has a clinical response to B12 eg symptoms improve, should be diagnosed with Antibody Negative PA.

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Thank you Sleepybunny that's really useful! I will definitely use that if I need to. No, what's that and it's link with B12d/PA?


MTHFR is a genetic variant that affects the efficiency of methylation processes but predominantly affects folate.

There are various other genes that can affect the way the body processes folate and B12 but these are operating at the cell level so wouldn't be explanations of the absorption problems you obviously have.

The dropping B12 levels are quite normal - how long people retain B12 varies a lot - although hydroxo is generally retained 2x as long as cyano there is a lot of variation and significant numbers of people actually retain cyano longer than hydroxo. It probably does mean that you need more frequent B12 shots though.

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Thank you! Yeah, I think I've always had the Hydroxo ones (Neo-Cytamen?) - and yeah, I feel like I need them every 6-8 weeks, that when I feel a noticeable 'drop' in function generally - been worse the last few months with various colds etc. but yeah, think that would be a start. So out of all the tests then, are there any that would be more useful to get than others in order to help me persuade them to give me more frequent shots?


not sure I can really help on the testing. The nature of the absorption problem isn't the issue with running out of B12 - it's the rate at which you remove B12 that is the issue and that is independent of the absorption problem = a different bit of your metabolism. If you have neurological symptoms then you could argue for 8 weekly as that is the BCSH recommendation ... and you could also try pointing your GP at the PAS website in the hope that they might educate themselves a bit about the problems with treatment regimes and may be be a bit more sensitive to your plight and those of others that they may be currently undertreating.


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Hi! This is my first post. Haven't even intro'd myself yet but feel the need to respond. I am in the US and have had multiple digestive problems from SIBO for years. My B12 has always tested great, and no doc would give me shots. 10 years later, still sick and now have had the antibody test and have it. No one ever did that before. I have probably had p.a. for 10 years. Now am almost paralyzed from waist down, hideous neck and head aches from big cervical spinal cord damage. Loss of balance, proprioception, lightheaded, hands getting numb, losing weight etc., etc. Subacute Combined Degeneration has been diagnosed. Doctors been looking for answers for 2 years, going to Mayo Clinic shortly. GET THOSE TESTS DONE! Find the answers or you could possibly end up like me.

I will you all the best,

Susan in FL


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