Confused About Test Results

[smerrill8]

Hi all,

I have a sister who was diagnosed with celiac disease and said that her Dr told her that all her immediate family members should be tested as well. I don't feel like I have any symptoms of celiac disease (I am tired a lot, but I have 5 kids and eat too much sugar! lol) but I've read that many people don't have typical symptoms but can still have it. I made sure to be eating lots of wheat for quite a while (weeks) before getting the blood tests done.

So today my blood work results came back and it looks like this:

Total IgA: 163 (said normal was 70-400)

Endomysial IgA: Negative

tTG: 14

The Dr said she didn't know how to interpret the results and I should go to a GI specialist for interpretation, but that there was a note on her lab report that the endomysial IgA is 99% specific for celiac and that if it's negative, I probably don't have it. She didn't know about the ttg number. Some websites I've read say that the ttg test can be normal up to 10, some say up to 20, some say up to 30. Does anyone here know which one I should go by?

Any interpretation of my results would be very appreciated! Thanks!

Sarah

[ravenwoodglass]

You should get a copy of the actual lab results. Those will show the reference range. Even a low positive is a positive. Was blood work done to measure things like your iron, ferritin, B12, etc? Sometimes we stop being able to absorb nutrients even while our GI system seems to be fine.

[Mother of Jibril]

Welcome to the group!

IMO, you have two options at this point:

1) Stop eating gluten 100% and assume you have celiac disease

2) Keep eating gluten, get tested for celiac disease on a regular (probably annual) basis, and hope that the damage isn't too bad by the time you get a positive result

I'm sorry your Dr. wasn't able to give you a clear interpretation, but it's a great idea to see a GI specialist! Adults can easily have celiac disease without the "typical" symptoms (abdominal pain, diarrhea, weight loss, etc...).

[curiousgeorge]

You need to get the lab ranges to know where you stand on it.

My doc did the antigliadin (igA and IgG) and the TTG blood work and my antigliadin IgA came back at 17 with a range of 20. He said he would consider that positive in and of itself because it was so high (the other two way over the range, 59 and 74 respectively, so it wasn't an issue). My thoughts on the TTG are that your body doesn't pump out antibodies against itself for no reason. Of course I am by no means an expert.

[farmer]

Did they do the following test:

endomysial IGA antibody titer

Normal is <1:5

This, according to my GI specialist, is the important test for celiac.

[smerrill8]

Yes, they did the endomysial IGA antibody test, but just came back with a "negative" response - they didn't provide a number.

Ok, so the lab says for the tTG IGA test that over 10 would be considered positive. Why is the 'positive' level over 10 at some labs and over 20 or 30 at other labs? As far as I can tell they're using the same units of measurement - is there one level that should be considered positive for everyone, assuming the same units are used? I was also tested 3 years ago and my tTG level then was 18, but they told me that under 20 was negative. Why?

Also, if the endomysial IGA antibody screen was negative, isn't that the more important test? My total IGA count was fine - I'm not iga deficient - so why would that be negative with a low positive on ttg? My sister's ttg was close to 200 when she was tested.. Sorry, I guess I'm confused!

[curiousgeorge]

Different labs have different ranges and not just for this, for lots of tests. Why? That I can not answer. Even your 18 with a range of 20 is highly suspicious but if your range is 10 and you have a 14 that is a positive. TTG is the autoimmune component and means that your body is doing damnage to itself. TTG is 95% specific as well.

[gfb1]

Different labs have different ranges and not just for this, for lots of tests. Why? That I can not answer. Even your 18 with a range of 20 is highly suspicious but if your range is 10 and you have a 14 that is a positive. TTG is the autoimmune component and means that your body is doing damnage to itself. TTG is 95% specific as well.

the reason for different ranges of results for different tests is due to different labs having different standard curves. there was a GREAT answer about how these test are done in another thread.

now, imagine this complex process being repeated in different laboratories, by different people, with different equipment and different reagents at different temperatures. the key is that the results should be internally consistent. it's a BIG mistake (and one frequently made by folks who are not trained as analytical chemists) to assume that the numbers are absolute.

you also have to be VERY careful regarding the 'high/low, but normal' discussion. you are either within the 'normal' range, or not. this comparison is a statistical descriptor of having 95% confidence that you are no different from the population average.

one problem is that there is NO SINGLE TEST. a good physician will arrive at a diagnosis based on several tests that match particular symptoms. alternatively, with regard to celiac disease, a lot of people in this forum (and, elsewhere) find through trial and error that they feel better and are no longer sick when they consume a gluten free diet. if the symptoms go away and you feel good (AND have no other problems) -- then perhaps that is the best diagnosis of all.