Intrinsic factor antibody test ranges??

I'm b12 deficient first diagnosed in 2012 by a reluctant GP. He ordered an intrinsic antibody test which was 2.4 Southend lab range 0-6. So this was normal. I've had treatment and b12 comes and goes according to my levels. However it's now 2016 and I've revisited this as I believe this is auto immune and PA. docs not bothered as treatment is the same, I am bothered tho! Why are the ranges so different from one lab to another, as 2.4 would be a positive for antibodies according to other labs. All doc will say is different methods.... But that is a big difference in range to my mind? I'm now having a paretial cells antibody test after mega insistence some 4 years later... I feel like they have tried to insinuate it's just poor diet and I'm unhappy and feel not properly diagnosed?!

6 Replies

  • The doc is correct, different types of assays, run on different machines, by different peoples sing different standard solutions can result in widely different 'normal' ranges.

    As far as I understand it the test doesn't give absolute values (like pg/mL or nmol/L). It's like asking a carpenter to measure a length of timber using another bit of wood. He'll be able to tell you that it's 6 and a bit lengths. Another carpenter would use a different bit of wood for a measure and tell you that it's almost 11 lengths. They're both right, but you can't compare their numbers.

    My diagnosis of PA was done without an anti-IF test. I persuaded my haematologist (who, in his first sentence, told me I didn't have PA because I hadn't had an anti-IF test) that the combination of low B12, positive anti-GPC and atrophied gastritis (as shown by endoscopy and histology) was PA.

    if the anti-GPC test comes back as positive then your doc may suggest that there are other possible causes. That's when you ask for a gastroscopy, so they can check for gastric atrophy. If that's positive then you've won the PA trifecta.

  • Thank you really helpful advice, just hoping to avoid the endoscopy but I have always suffered from a really bad stomach from heartburn to upset stomach issues! I'm as thin as a rake I know I need to bite the bullet!

  • If you do have Autoimmune Metaplastic Gastric Atrophy (AMGA - the condition that causes PA) then a gastroscopy is a good idea.

    People with AMGA are at a higher risk of developing Gastric Carcinoids (aka Neuroendocrine Tumours - NETs). Although these are rare and are normally indolent (my gastro's favourite word to describe them) they do need monitoring to make sure they're behaving themselves.

  • Good idea to have one done then, at least once to see. And I know it sounds bad, but I've had three and it's not so bad as many people think (it's more the thinking/stress that makes them bad than the thing itself) if you lie very still and focus on breathing it can be done in under 10 minutes. It's possible to have them give you some sleeping-stuff so you don't notice much. Don't know the rules in the UK. Here in Greece you always have to have that, I had a fight cause I didn't want it. In Holland it's the other way round, you have to ask to get it.

  • I was asked if I wanted a sedative or a local anaesthetic throat-spray. I opted for the latter as I wanted to be awake - and watch it all on the TV.

    My first one was fine, as was the second when they went in to remove a (benign) polyp. The third was a bit intense as they were checking to see the distribution of my NETs and took 32 biopsy samples. And it was a new machine set up the wrong way round so I couldn't see the TV.

    I'm of for my fourth in 4 week's time. Just to check that the NETs are still dozing. I'm expecting that one to be a bit boring.

  • Thank you all for the advice had the blood test today for paretial cells so let's see what comes back. Then perhaps that's the route to take :)

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