TTG questions

[CeliacMommaX2]

Our daughter has been strictly gluten-free for over 2 years now.  She's had labs checked every 3-6  months and this is what we've seen (TTG only):  69, 73, 81, 41, 64, 14.  They are telling us she's "negative" now that her TTG is at 14 (looks like the reference range on the lab is negative is <15).  I'm seeing other places where <10 is negative, or <20 is negative... can anyone explain this to me?  What does this mean?  What do celiac's typically see with their TTG levels?  

Thanks!

[Gemini]

Here is a quick explanation of lab testing reference ranges:

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It is important to use the same lab for re-testing antibody levels for a more accurate comparison.

Her antibody levels are coming down so that is a good thing. However, the doctor should also be retesting her DGP, which tells you if she is getting any gluten in her diet.  The tTg is for intestinal damage and it can be elevated with other autoimmune disease. I still can't believe that docs only test tTg because it is important that the DGP be as low as possible as it correlates to dietary consumption of gluten. 

I have been gluten-free for 12 years and after the first year, my DGP (or the older version, the AGA IgA, which was all that was available at the time) was 1-2 and I have held it there since going gluten-free. But you shouldn't worry about the tTg so much as it is in the normal range and will probably come down even further the longer she is gluten-free. Ask them to repeat the DGP....it is important to know that number also.

 

 

[RMJ]

When a lab test measures something like total IgA antibody or cholesterol, the result is a real unit - a weight per a volume.  Reference ranges may differ a little between laboratories but actual patient results can be compared from one lab to another.

For celiac specific antibody tests such as TTG, the units are completely arbitrary and assigned by the manufacturer of the test.  A "4" from one manufacturer who says normal is <3 is NOT the same amount of antibody as a "4" from a manufacturer who says normal is <20.  It is NOT a case of one lab deciding there has to be more antibody to be considered positive.  When developing the tests (I used to do this type of work) the manufacturer has blood samples from known celiacs and known non-celiacs, looks at the results obtained from a bunch of samples,  and chooses a cutoff for normal that classifies most results correctly.  This is why results from different labs who use tests from different manufacturers cannot be compared.  Hope this helps.

Congratulations on getting your daughter's antibody level into the normal range!

[cyclinglady]

Congratulations!  

[CeliacMommaX2]

Thank you for the congrats!  We were thrilled to have her TTG finally come down.  We were prepared and about to start the Fasano diet if it wasn't!  We're actually having a bit of a hard time believing it is actually down and are trying to determine if it is because we also recently cut quinoa from her diet.

Thank you also for the information about the labs... that makes so much more sense.  They have been testing EMA and TTG only.  (EMA is now negative too!!!)  We asked the GI last year if we should start checking DGP and she said it was pointless at this point since it wasn't tested for initially.  Thoughts on that one?  Should we request it?

Thanks again!

[RMJ]

I would want the DGP also.  My TTG started out high and now is just barely normal; my DGP is lower than at first but still high and per an endoscopy I still have some villi damage.  

[Victoria5289]

On 5/10/2017 at 3:54 PM, CeliacMommaX2 said:

Our daughter has been strictly gluten-free for over 2 years now.  She's had labs checked every 3-6  months and this is what we've seen (TTG only):  69, 73, 81, 41, 64, 14.  They are telling us she's "negative" now that her TTG is at 14 (looks like the reference range on the lab is negative is <15).  I'm seeing other places where <10 is negative, or <20 is negative... can anyone explain this to me?  What does this mean?  What do celiac's typically see with their TTG levels?  

Thanks!

I don't think it's anything to do with celiac but it's sounds like a problem with whey