First Test Positive. Second Test Negative?

[Shaun]

My 4-year old daughter is autistic, and her neurologist recommended an IgA test for celiac disease.  The first time it came back positive.  However, she was gluten-free for three months preceding that test.  I have heard of false negatives, but never a false positive.  Is it possible to get a false positive when being gluten-free for three months?

 

After the positive test, we did a gluten challenge for a month and did the IgA test again.  It came back negative.  Now we are unsure how to proceed.

 

If we wanted to get a complete celiac disease panel on our own, what tests would we need to order from Open Original Shared Link?

 

Thanks!

 

[cyclinglady]

Here is the complete list:

-tTG IgA and tTG IgG

-DGP IgA and DGP IgG

-EMA IgA

-total serum IgA and IgG (control test)

-AGA IGA and AGA IgG - older and less reliable tests largely replaced by the DGP tests

-endoscopic biopsy - make sure at least 6 samples are taken

(Source: NVSMOM -- )

Can the doctor re-take and include the DPG and EMA tests? That would be the normal procedure if the TTG test results were inconclusive and you would not have to pay out-of-pocket.

Welcome to the forum and let us know how it goes!

[Shaun]

Thank you for the information.  What does DGP stand for?

[cyclinglady]

Here is a link from the University of Chicago's celiac website (leading researcher) that explains the tests (and I do not have to type).

Open Original Shared Link

[nvsmom]

LOL  

 

DGP is deaminated gliadin peptides.  Don't let the doctor mix them up with the AGA tests (anti-gliadin antibodies) - they aren't as good of a test.

 

Test results can linger elevated for months, or even a couple of years, after going gluten-free - especially the tTG tests.  I know that my tTG IgA was still slightly elevated after being gluten-free for about 9-10 months, but it was normal when I recently had it rechecked, after almost 3 years gluten-free.  Those tTG tests can be slow to change, and that works in the reverse too.  The tTG tests need a gluten challenge (normal diet) of 2-3 months to reliably (as much as possible anyways) give a accurate test result. One month may not be enough.

 

If you feel unsure about committing to the gluten-free diet, I would have her eat gluten for 2 more months and then get all of the tests done, as well as the endoscopic biopsy (6 or more samples).  

 

If you just have a bit of doubt that it might be celiac disease, perhaps get the genetic tests done (DQ2 and DQ8). 97% of all celiacs have those genes, so if she doesn't have at least one, then her chances of being a celiac are much less.

 

Or if you think it was probably celiac disease, have her stay gluten-free and observe and record her recovery over the next 6 months or so.  Going gluten-free is not a quick fix like it is for allergies. It can takes months for the body to even start recovering.

 

Best wishes.