Will B12 skew PC and IF results

Hi, I have been having injections of hydroxocobalamin from my doctor every 3 months since I was diagnosed in 2011 with PA, level was 140. At my injection 3 months ago, the nurse told me that the doctors want all their B12 injection patients to have a parietal cell antibody test.

This came back negative and my injections were stopped. I went to the GP and he has given me one this month but wants me (and every other B12 patient) to have the Intrinsic factor test also.

My question to the group is - will the fact that I have had the injection skew the test results in any way?

Thank you for being a wonderful group.

28 Replies

  • I don't know if they skew results, the experts on here will let you know. But I do know that getting a negative result from either test doesn't mean they should stop your injections! Grrrrrr that makes my blood boil. You need them for life so your GP is ignorant as most are about b12. I think that Martyn Hooper, the founder and chair of the pernicious anemia society was tested negative twice before finally being diagnosed. The guidelines state to treat symptoms and not rely on the test results. :-)

  • Thank you LtAngua52, I thought as much, but wasn't sure. The GP surgery is doing this to everyone and when I asked why the doc said 'we are finding that there are a lot more people on B12 these days'!

    The PAS office is closed this week that's why I asked on here. Also can't seem to find as answer on line - I have tried googling it.

  • Probably trying to save money. Meanwhile patients will become sicker and end up on drugs that are vastly more expensive! The mind boggles with the lack of logic. You could always self inject like the rest of us!

    Have you tried looking on the bcsh website? :-)

  • I don't understand why your injections have been stopped. UK B12 recommended treatment makes it clear that once diagnosed with PA, treatment is for life.

    I assume that if you were diagnosed on the past you may have had a positive IFA or positive parietal antibody test in past. Some people get copies of their complete medical records. Recent docuemnts make it clear that its symptoms GPs should be focussing on.

    See following sources for info on UK B12 treatment.

    1) BCSH Cobalamin and Folate Guidelines page 8. I found page 29 useful too.

    2)http://patient.info/doctor/pernicious-anaemia-and-b12-deficiency See Management section for treatment info based on BNF (British national formulary)

    3) BNF Chapter 9 Section 1.2

    4) nhs.uk/Conditions/Anaemia-v...

    5) treatment is mentioned in Martyn Hooper's book "What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency"

    I'd urge you to contact the PAS (Pernicious Anaemia Society). The office is closed until June 15th but you should be able to leave a phone message. The PAS can sometimes intervene on members behalf. Lifetime membership costs £20.

    Just seen this about helpline not working.http://www.pernicious-anaemia-society.org/read-news.php?news=140

    pernicious-anaemia-society.... 01656 769 717

    There are stories of similar cases to yours on Martyn hooper's blog. He describes how he can help members who have had their injections stopped.



    Fbirder has a useful summary of mainly UK B12 documents that may be helpful. If you search for his posts you should find a link to his summary. I gave a copy of the BCSH Cobalamin and Folate Guidelines and a copy of Martyn Hooper's book to my GPs.

    I really think Martyn Hooper would be interested in hearing about what your surgery is doing.

    Link about writing to GPs when unhappy with treatment.


  • Thank you sleepybunny, I have already spoken to Martyn Hooper last week and have told the doc what he said (also left him a copy of the latest newsletter of PAS). He did give me the injection there and then but, said the surgery (which is in Anglesey, North Wales -incase is helps anyone else), is now testing everyone on B12 for Parietal cell and intrinsic factor antibodies.

    He has changed my prescription to 50mcg tablets twice a day, which I will not be taking - but have copied incase of a future dispute. I cannot ever remember having these tests in the past other than the serum test.

    I began on B12 in 1984 whilst pregnant after a test which involved taking a sample of my bone marrow in hospital, I do not remember how many years I had the injections for but it was a long time, then along the way I was tested again and these stopped.

    I have told him that if he stops my injections I will be contacting Martyn again and will not hesitate to self inject if need be. I also told him that my son, mother, brother, sister and numerous cousins aand nieces are also on B12.

    Many thanks for all your help

    PS I have prepared a letter to request copies of my health history, but since I know it will be huge because of my age I'm leaving that as a last resort.

  • will the fact that I have had the injection skew the test results in any way?

    I've recently added this subject to my summary document - frankhollis.com/temp/Summar...

    We had a long discussion about this a few weeks back and the final conclusion was that the answer to your question is No. Or maybe Yes.

    It all depends on what assay they use. In the 1980s the assay would be affected and they recommended a 3 week interval. That assay used radioactive cobalt, which is no longer available - so the assay is no longer used. But that idea of B12 interfering with the anti-IF assay has hung on.

    In the late 1980s a new assay was developed that could still suffer interference with very high levels of B12. The recommendation is to leave a gap of 2 or 3 days.

    About a decade ago a new assay was developed that doesn't suffer any interference.

    Unfortunately, you won't know what assay will be used and, I bet, neither will your doctor.

    Both the anti-GPC and anti-IF tests can give false negatives (20% and 50%, respectively). So failing either test isn't proof that you don't have PA.

    NICE say that doctors shouldn't use the anti-GPC test -

    Anti-parietal cell antibody is found in 80% of people with pernicious anaemia, but also in 10% of people without it. However, it has a low specificity of about 50%, which is much lower than that of anti-intrinsic factor antibody [Andres et al, 2004]. If anti-parietal cell antibody is not present it is unlikely that the person has pernicious anaemia, but its presence is not diagnostic as it can occur in other conditions (for example atrophic gastritis) and older people (16% of normal women over 60 years of age) [Carmel, 1992; Hoffbrand et al, 2006]. As a result, it is no longer recommended as a diagnostic test for pernicious anaemia [Devalia et al, 2014].

  • Thank you fbirder, very interesting and useful information. I have printed these out and will show or give them to the doc if need be.

    Thanks again

  • Note that all those problems with new or old test are actually about false positives - i.e. the test could show that you have IF antibodies when you don't - so not a problem for you, just for your GP.

  • A positive IFA test result is not needed for a diagnosis of PA (pernicious Anaemia) in some people.

    The BCSH Cobalamin and Folate Guidelines mention "Antibody Negative Pernicious Anaemia" on page 8, 10, 11, 12 , 29.

    NHS Wales complaints


    I did wonder whether your MP or the welsh minister for health might be able to tell you if the BCSH Cobalamin and Folate Guidelines are being followed in Wales.

  • Thank you, I will be looking into this

    I did wonder whether your MP or the welsh minister for health might be able to tell you if the BCSH Cobalamin and Folate Guidelines are being followed in Wales

  • I had a test for I F antibodies when I had been supplementing madly on sublingual B12 lozenges and my body was plastered with B12 patches'. My B12 level was sky high. In spite of this my I F antibodies showed up, so I had PA.

    I assume from this that the test results were not skewed .

    I also had the anti-parietal cell antibody test and it was negative But I still had PA! .

  • Oh, good news wedgewood, I won't have to worry about having the test then. Thank you very much

  • What the **** is going on with the medical profession and the NHS???????!!!!

    Never had much faith in them anyway but the more I hear about the way patients who have been receiving B12 for years are being treated ....

    (at which point I have to reflect that it being a weekend I haven't had as much B12 as I would normally have had so I'm probably a bit low and hence temper is a bit short)

    may be the reason why more B12 is being used is because people are becoming more aware of it ... it could also be an aging population as it becomes more common as you get older.

    This is all so incredibly stupid - stop treating people with an injection costs less than a £ so in a few years they are all suffering from irreversible dementia and in need of expensive continual nursing care. Talk about short sighted.

    Really do hope that you manage to get somewhere with all of the information from fbirder and support from the PAS

  • Not to mention increasing numbers of people having gastric surgery, widespread use of PPI's and Metformin....

    You are spot on in your assertion that this is short-sighted penny pinching. Talk about spoiling the ship for a ha'porth of tar.

  • Thank you Gambit62, that is exactly what I told the doc. Also pointed out to him that according to NICE the tablets cost £2.99 per pack and injection approx 70p every three months - does not make sense!

  • Nurse's time I should think is the cost, which is why it would make so much sense if we could buy injections OTC.

  • Exactly, that's why I told him I'd be willing to do my own - he didn't have anything to say about that.

  • I'm a bit confused about autoimmune antibodies in general. They seem to come and go and I've read of people with other autoimmune conditions having treatment stopped due to the antibodies not showing in the test. Some people seem then able to show or prove they do have the illness despite being antibody negative (eg, as in Frank's document: AbNegPA) and continue to get treatment but how they prove this I have no idea. I asked an endocrinologist about autoimmune thyroid disease and he said 'just because someone has the antibodies doesn't mean they have the disease' which was very puzzling (especially as going to see him or another specialist and having the test would normally be due to having symptoms!).

  • Same here frodo, that's why I posted the question. I too am on thyroxine.

  • I've noticed on other forums that some people with autoimmune thyroid disorders are being advised by medics or are discovering for themselves that it helps the condition to be gluten free. So I wonder if going gluten free somehow 'switches off' or 'dials down' the thyroid autoimmune response - in which case, would retesting then NOT show the antibodies??

    Just wondering how it all works.

  • No idea if that would work but, I did have a particularly difficult time with my health about 12 years ago and went gluten free as a last resort, it lasted for about 6 months and felt much better for it. It's not easy to do as have to check all ingredients in everything.

  • I know, I'm gluten free myself - it's a nightmare and very expensive. But much improved health.

  • Your GP's arrogance is astounding and looks to me like a cynical excuse to reduce having to give patients B12 injections, as the parietal cell test is usually carried out to exclude the possibility of PA causing absorption issues before treatment with B12. There are several reasons why you could be B12 deficient (see page 4 of the research document below - 'Identifying the cause....'. ). Refusing your injection based on a further parietal cell test only is endangering your health as, according to latest BMJ research there is no reliable test anyway.

    It might be worth showing your GP the summary of the latest BMJ research document :


    Summary points

    "Vitamin B12 deficiency is a common but serious condition

    Clinical presentation may not be obvious thus leading to complex issues around diagnosis and treatment

    *There is no ideal test to define deficiency and therefore the clinical condition of patients is of the utmost importance

    *There is evidence that new techniques such as the measurement of holotranscobalamin and methylmalonic acid levels seem useful in more accurately defining deficiency

    *If the clinical features suggest deficiency then it is important to treat patients to avoid neurological impairment even if there may be discordance between the results and clinical features "

  • True, but this time he wants to do the Intrinsic factor test, which I have agreed to have. It does look like money is the main reason for this because they're going to test everyone who's getting the B12 injection.

    I have printed off these points. Also have told him that as a last resort I will self inject but, not without taking things a lot further. So many members of my family have these including my son - so will certainly not stop there!

    Thanks for your input, hope things a well with you.

  • You probably already know that family history is another huge factor as B12 builds DNA and I believe research states that you have a 40% risk if it is already in the family. In any case, it seems that you had already been diagnosed and UK medical guidelines stipulate that treatment for PA is for life.

    More ammunition:

    In case you haven't already seen it, Martyn Hooper has PA but tested negative for IF:


    I hope all goes well for you.

  • Thank you Polaris will have look at his blog

  • "I also told him that my son, mother, brother, sister and numerous cousins aand nieces are also on B12. "

    Info from PAS website about who is most at risk.



    Does your GP have it written down that other family members have B12 deficiency/PA?

    I sometimes put things I want my GPs to remember or think about, in a letter as letters have to be filed in your notes and are a permanent record of issues raised.

  • That's a very good idea. Had a look at your links - interesting. Will probably do this. Thank you

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