Blood results false positive

[Dee21]

Hi,

I have been gluten free for 6 weeks and only just been tested. I was doing an elimination diet out of curiosity for a rash on my feet and multiple other symptoms and long story short, have had the results today. Currently waiting to speak to my doctor but can't get my head around a 'false positive' result. Does anyone know what this means please, result written as follows:

Anti TTG IgA    4 units   (0-20)

IgA                    2.9 g/L  (0.8 - 4.0)

Thanks so much.

[trents]

Welcome to the forum, Dee21!

First, it was not a good idea to go gluten free before being tested. That can invalidate the test but usually in the direction of a false negative.

Second, it is curious that your doctor ordered a test for Celiac Disease and then when the results indicate you do indeed have it to call it a false positive. Did you ask the doctor to explain this?

Third, are you sure you were truly eating gluten-free for that six week period? Most of us find that avoiding gluten altogether is quite an education process as wheat/barley/rye can be disguised by terminology and can find it's way into the foods, supplements and meds we consume through cross contamination. Recent studies show that most people who claim to be eating gluten-free are actually eating low gluten. Perhaps the doctor's "false positive" diagnosis was based on the assumption you had eliminated gluten entirely from your diet when, in fact, you had only eliminated major sources of it. Is this doctor a GI doc or a GP? 

[cyclinglady]

You must be consuming gluten (about 1 to 2 pieces of bread daily or equivalent) for any celiac disease test to work as Trents indicated.  Talk to your doctor about retested after you go back on gluten for a minimum of 6 weeks.  

[Dee21]

On 10/6/2020 at 3:00 AM, trents said:

Welcome to the forum, Dee21!

First, it was not a good idea to go gluten free before being tested. That can invalidate the test but usually in the direction of a false negative.

Second, it is curious that your doctor ordered a test for Celiac Disease and then when the results indicate you do indeed have it to call it a false positive. Did you ask the doctor to explain this?

Third, are you sure you were truly eating gluten-free for that six week period? Most of us find that avoiding gluten altogether is quite an education process as wheat/barley/rye can be disguised by terminology and can find it's way into the foods, supplements and meds we consume through cross contamination. Recent studies show that most people who claim to be eating gluten-free are actually eating low gluten. Perhaps the doctor's "false positive" diagnosis was based on the assumption you had eliminated gluten entirely from your diet when, in fact, you had only eliminated major sources of it. Is this doctor a GI doc or a GP? 

I am so sorry, that should have said false negative, I had returned to a gluten containing diet and can only blame the brain fog! Currently doing a 4 week gluten challenge, 3 days to go and it's been hell! I stumbled across celiac by accident and if I had known I would never have gone gluten-free. My 'doctor' turned out to be a nurse practitioner (no offense to any NP but she was off the ball) who has actually been reported for the way she has dealt with me as I asked her when I was 1 week into gluten-free diet to be tested and she refused but did the test 5 weeks later! Now have a lovely GP and we are starting again. So sorry for the confusion and thank you for your reply.

On 10/6/2020 at 4:58 AM, cyclinglady said:

You must be consuming gluten (about 1 to 2 pieces of bread daily or equivalent) for any celiac disease test to work as Trents indicated.  Talk to your doctor about retested after you go back on gluten for a minimum of 6 weeks.  

Apologies, that should have said negative, brain fog moment! 

[RMJ]

You may also want to ask for a more complete panel of tests.  You got the TTG antibody test, there is also a DGP (demidated gliadin peptide) antibody test.

[Dee21]

8 hours ago, RMJ said:

You may also want to ask for a more complete panel of tests.  You got the TTG antibody test, there is also a DGP (demidated gliadin peptide) antibody test.

Thank you, no clue if they do it here in NZ but will ask on Monday.