Possible Iga Deficiency?

[igadeficient]

Hello.

Just to clarify, my username is what it is purely based on the questions i pose, dont mean to be misleading . I was directed here by a friend of mine since we've both suspected Celiac disease as a cause of various symptoms. Well I went to the doctor and got an iga antibody blood test for Celiac disease. The result was '<1 U/ml' with a range of 0 - 4. I was okay with my negative result until I talked to said friend and he let me know about possible iga deficiency! I'm not quite sure what all this means if I'm totally honest, other than I could still have celiac! I was just wondering what is the likelihood of being iga deficient? I mean I find it quite unlikely - I've never been told I am or even heard of it prior to this?? & also with my result of less than one, is that any sort of indicator as to whether I am? I'm just pretty overwhelmed with all this info, and would really appreciate some help

[mushroom]

Hello, and welcome to our place.

The following is the complete list of the tests available to test for celiac disease:

Anti-Gliadin (AGA) IgA

Anti-Gliadin (AGA) IgG

Anti-Endomysial (EMA) IgA

Anti-Tissue Transglutaminase (tTG) IgA

Deamidated Gliadin Peptide (DGP) IgA and IgG

Total Serum IgA

The first two are the older tests and many docs don't use them any more. The Anti-Tissue Transglutaminas (tTG) IgA is the favorite of the docs because it is the one they are most familiar with. If this is positive then often the EMA will be run too. The new one, Deamidated Gliadin Peptide, has the most specificity for celiac disease but the docs aren't familiar enough with it yet. And the last, the Total Serum IgA, measures whether you make normal amounts of IgA antibodies. (We all make antibodies - that is how we acquire immunity to things, as in vaccinations and the like) If your total number of IgA antibodies does not fall within the lab's normal range, then any IgA testing done on you is not valid; this is why it should always be run. You then have to be tested with IgG antibodies. Strangely, I have read that people with celiac are more likely to have a low total IgA; I wonder if this is why many of us have been sick with respiratory viruses most of our lives - unable to develop any immunity to them???

I am assuming that the test your doctor ran was the tTG IgA. Can you convince him/her to run the Total Serum IgA and the DGP, IgA and IgG?

[igadeficient]

Thank you mushroom, very informative I'm not sure what the actual test does but it does say on the sheet (I asked for a copy) that its an iga test, so deficiency can render it false.

Is my low level of iga (less than 1) indicative at all? I know I need to ask for the other tests now, but was just wondering if this could be significant at all.

[NJceliac]

  On 2/17/2013 at 12:09 AM, igadeficient said:

Hello.

Just to clarify, my username is what it is purely based on the questions i pose, dont mean to be misleading . I was directed here by a friend of mine since we've both suspected Celiac disease as a cause of various symptoms. Well I went to the doctor and got an iga antibody blood test for Celiac disease. The result was '<1 U/ml' with a range of 0 - 4. I was okay with my negative result until I talked to said friend and he let me know about possible iga deficiency! I'm not quite sure what all this means if I'm totally honest, other than I could still have celiac! I was just wondering what is the likelihood of being iga deficient? I mean I find it quite unlikely - I've never been told I am or even heard of it prior to this?? & also with my result of less than one, is that any sort of indicator as to whether I am? I'm just pretty overwhelmed with all this info, and would really appreciate some help

I have IgA deficiency. In general population, the prevalence is about 1/500 however in celiacs there is a much higher prevalence. For a lot of labs, they automatically check your serum total IgA levels if the tTG IgA is negative to make sure it isn't a false negative. If Total serum IgA is low or absent, they automatically run a tTG IgG. I happened to know about my IgA deficiency before being tested for celiac. Most people with IgA deficiency don't know they have it and are asymptomatic.

[mushroom]

No, a very low tTG IgA is not uncommon; it does not have any particular meaning except, standing alone, it is negative for celiac. It would have even less meaning if your total IgA was below range because we wouldn't even know if it was accurate..

[igadeficient]

Ah thanks to the both of you I do have another question, say I'm not iga deficient, is it not possible to get a false negative? I've been reading about the biopsy "being the gold standard for testing," so I was just wondering whether this is something I should enquire with the doc about getting?

[kareng]

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"In blood tests, are false positives less common than false negatives?

Even though blood tests are quite accurate, they are falsely positive 1-3% of the time (i.e., being positive without the person having celiac) and, although less commonly, falsely negative 1-2% of the time (i.e., being normal when a person actually has celiac)."