Thyroid UK
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IgA levels. Confused!!

Sorry to be a pain folks, I've just noticed something in tiny writing on my blood test print out I got on Friday, that I don't understand.

I have found myself a good nutritionist that I am booked in to see next week but I wonder if anone on the site knows anything about IgA levels. I skimmed over my result, as I thought this was my coeliac test result and I'd been told that was normal and as it is at level 1 u/mL and guideline is < 10.00/mL on the printout, I read on BUT I've just read in tiny print underneath that, it says ' Please note: this is an IgA auto antibody test. False negatives occur in those with IgA deficiency.'

I'm probably being incredibly thick but I thought coeliac tests were pretty conclusive and if antibodies were present, a biopsy on the villi was done for confirmation of the disease. I don't understand how IgA deficiency is measured and if 1 is okay, then how does one know if it's a false negative?

That probably sounds as clear as mud but can some wiser soul than me, clarify this for me, please.

Thank you very much.

8 Replies

Some people can't produce the antibodies, that's why besides the celiac antibodies they should also test if your body can even produce the antibodies. If not than a blood test gives no information and a biopsy would be the only way to test.


Oh, right. Well, if I'm producing antibodies for other things (my body was able to show raised antibodies for the Hashimoto's before Christmas, so presumably I could produce them okay for coeliac, if I had them) . Is that correct? How do you know if your body can't produce antibodies?

Thanks so much for your help.


I don't know if it's for all antibodies or just for IgA..When they tested me for celiac (blood test) they tested IgA, IgG and tTG. Last one is for celiac and is a IgA antibody.

If I understand it right than the people who are not capable of producing the IgA antibodies will have none or a really low IgA result.


All, I know is that my blood form said 'coeliac screening' when I had the blood test done but the IgA is the only one mentioned on this last batch of tests. I had tried to Google a marker system but didn't have a lot of luck and just assumed my level of 1 is good as its under 10. I don't know if Igg and tTg were tested.

I know the nutritionist now has my permission to access my medical records so perhaps she can check that on Wednesday. Thanks again for your help, Flower 3.


Hi Chocoholic, I have low IgA problems. If you look at the bottom limit on your test results, you have a problem if you are UNDER that. For example, the bottom limit for 'normal' on my test results should be 0.8 and mine are 0.73. What it means is if you have low IgA the standard tests they do for coeliac disease will possibly give a false negative. This is because your body doesn't produce enough IgA. The standard test is the Anti TTG- Iga. You need to have a different test taken - an IgG test. This tests for IgG antibodies instead.

So check what the lab gives as their bottom line for normal. If you are over that, then you are fine!


Thank you for your response,Chancery. I'm still confused.

I assumed my doctor would have done all the relevant tests for coeliac.

As I have other closely related autoimmune conditions, wouldn't he have done all the tests in one go,especially antibodies tests?

They lost my first coeliac test, which delayed my results by a month and both my vit D2 and D3 are out of range which they didn't even tell me and I am seeing a nutritionist next Wednesday but I'm getting so confused with all the markers that need checking for various conditions. They won't check my T3 for Hashimoto's and I only know a little about coeliac disease testing and to be honest, I seem incapable at the moment of absorbing new information. I read things and don't understand them.

I used to work in a library, so am not stupid but it scares me that my brain seems unable now to understand so little about my increasing health problems.

Sorry for rambling. I'll re-read your reply tomorrow to try and understand what you are telling me. I do appreciate you trying to help.


Hi chocoholic, no need to apologise for rambling or confusion. I often have to read paragraphs four times in a book and STILL can't take the information in! It has made life and learning VERY slow.

You should have had at least two coeliac tests. The IgA one, the Anti-TTG Iga and POSSIBLY one to test for C-reactive protein. This one just tests to see if there are any inflammation markers in the gut. There's a good chance your doc has done two of them or all three and the results just aren't through yet. Sometimes they don't all come at once.

If he HAS only done the IgA test you need to ask him to have at least the Anti-TTG Iga because the IgA alone is NOT considered a reliable marker. Point him towards the NICE guidelines if he refuses. That should change his tune!

P.S. To write this I had to consult all my own blood tests and read them off carefully and copy them - just to reassure you how idiotic I am too!


Thank you so much. I understand a bit better now. I will try and find out exactly which tests been done. My IgA result level of 1 is listed alongside a <10 , so does that sound an okay level to you?


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