Test Result Interpretation

[Zoe246]

I had a test following symptoms and as relatives have coeliac disease, and was told the test was ‘borderline’ and needed repeating and the second test had exactly the same results to the decimal point, which they then said they wouldn’t review further as was okay. I was just hoping for someone to confirm this as it was exactly the same result so wasn’t sure how it could be considered borderline and cause for concern the first time, but the same result be okay the second time. Just want to be completely certain that it is something causing the symptoms. Results below. Thanks in advance.

IGG ANTI-TISSUE TRANSGLUTAMINASE AN < 0.6U/mL [<7.0]; IgG TTG has lower specificity and sensitivity than IgA TTG

IGA ANTI-TISSUE TRANSGLUTAMINASE AN NA Inconclusive IgA TTG result, possibly due to low total IgA

[trents]

The information you give seems incomplete. Did you have another test done to measure total IGA that showed total IGA was low or is the comment to that effect in your post just putting forth a possibility? Low total IGA can result in false negatives for the IgA TTG result.

The data with the IgA TTG is confusing but it looks like the [<7] must refer to the reference point separating negative from positive and the <0.6U/mL is your actual score. If I'm understanding that correctly, that test is negative for celiac disease.

By some chance had you already started in on a gluten free diet before the blood draw for the tests was done?

[Zoe246]

Hi, thanks for your reply.

The IGA on the second line was the IGA result I thought, those were there 2 test results they gave, sorry I don’t really understand the results too clearly. The test results had the comment re ‘possibly due to low total IGA’

[Zoe246]

I was eating gluten throughout both tests (sorry forgot to add to the last message)

[trents]

IGA tTG is not the same as total IGA. IGA tTG is a particular antibody associated strongly with celiac disease. Total IGA is the whole mix of IGA antibodies which includes tTG but others as well. If total IGA is low it can drive down individual IGA scores, including the tTG IGA.

[knitty kitty]

@Zoe246,

Looks like you had a low tTg IgG.  Your tTg IgA result is low because your total IgA result is low.  

If you're not producing sufficient IgA in general (total IgA), then the doctors cannot/should not use low tTg IgA to make a diagnosis.  

Total IgA and tTg IgA production can be affected by anemia and deficiency in Thiamine Vitamin B1.  Malabsorption of vitamins is symptomatic of Celiac Disease.  

Another test, DGP IgG, should be done for further clarification.  

Also, a genetic test for the Celiac genes would be beneficial.  Having the genes for Celiac means you have the potential to develop Celiac.  Your genes may already be switched on if you are having symptoms.  A gluten free diet would be beneficial in either case. 

 Hope this helps!

[trents]

But don't start a gluten free diet until all testing for celiac disease is done if you intend to go for more testing. This doesn't apply to the genetic test which is not a test for celiac disease per se.

[Molerey]

It's crucial to distinguish between IgA tTG and total IgA levels, as low total IgA can affect the IgA tTG test results. Given your continued gluten consumption throughout the tests, the results suggest a negative diagnosis for celiac disase. However, the mention of potentially low total IgA levels indicates that further clarification through additional tests like DGP IgG might be necessary. Also considering genetic testing for celiac disease could provide more insight, especially before starting any gluten-free diet.

[Scott Adams]

This article might be helpful. It breaks down each type of test, and what a positive results means in terms of the probability that you might have celiac disease. One test that always needs to be done is the IgA Levels/Deficiency Test (often called "Total IGA") because some people are naturally IGA deficient, and if this is the case, then certain blood tests for celiac disease might be false-negative, and other types of tests need to be done to make an accurate diagnosis. The article includes the "Mayo Clinic Protocol," which is the best overall protocol for results to be ~98% accurate.

 

 

[Zoe246]

These comments are all really helpful, thankyou, it’s much appreciated