Explain hashimotos and celiac false positives

[NovemberNewbie2023]

Hello,

I keep reading that hashimotos can cause a false positive for celiac. How does one determine if they had a false positive? Is a scope the only answer? My doc is having me eat gluten and redo the TTG IGA but what’s the point if I have hashimotos…. If by chance I don’t have celiac, won’t the false positive continue to happen?  

Background:

After two miscarriages, my fertility doctor did a number of tests and in Sept I was told I have hashimoto’s and have started a thyroid med. I was also (shockingly) told I tested positive on my TTG IGA (celiac). I went gluten-free immediately at the advice of my endocrinologist. My family doctor, however, wanted me to repeat the bloodwork due to me never having any of the regular negative symptoms from gluten. Unfortunately when I redid the bloodwork, I had been gluten-free for two weeks. Bloodwork came back negative this time. At this point, we’re unure if it was a false positive (apparently that can happen if you have other autoimmune diseases) or it was negative due to me being gluten-free for that short time. 

Fam doctor is recommending I eat gluten again for 6 weeks and redo the bloodwork so I know for sure. I don’t mind but I hate that I’m also trying to conceive and this could interfere. 

[trents]

Welcome to the forum @NovemberNewbie2023!

I have not heard or read that Hashimotos can cause a false positive in celiac disease antibody testing. But I am aware that Hashimotos is more common in he celiac population than in the general population. Also, the tTG-IGA is highly specific for celiac disease and it is highly unlikely that something else is causing it to be elevated. There are also other antibody tests that can be run to check for celiac disease: 

Since you do not have classic celiac symptoms, is there a reason you cannot undertake the gluten challenge in order to be retested? You would need to eat the gluten equivalent of 2-3 slices of wheat bread for  6-8 weeks to ensure the antibody testing is accurate. By the way, not having classic GI symptoms with celiac disease is much more common than most doctors realize. Many docs are operating on very dated information, especially those who have been out of med school for a long time.

Edited November 29, 2023 by trents

[Scott Adams]

I agree with @trents. 

Hashimoto's thyroiditis, an autoimmune condition affecting the thyroid, is generally not known to directly cause a false positive tissue transglutaminase immunoglobulin A (TTG IgA) test for celiac disease. The TTG IgA test is specific to celiac disease and measures the presence of antibodies that may indicate an autoimmune response to gluten.

However, it's essential to note that autoimmune conditions often coexist, and individuals with one autoimmune disorder may have an increased risk of developing others. Hashimoto's and celiac disease are both autoimmune disorders, and studies have suggested an association between the two. In some cases, individuals with Hashimoto's thyroiditis may be at a slightly higher risk of also having celiac disease.

The reasons for this association are not entirely clear, but it may involve shared genetic factors or immune system dysregulation. That being said, having Hashimoto's thyroiditis does not directly cause a false positive TTG IgA test result for celiac disease.

Given your symptoms and history, I would not eat gluten again, especially if your symptoms have improved after going gluten-free.

[Wheatwacked]

" because of our long winters, most Canadians make little or no Vitamin D between October and March and need to get it from other sources. " Vitamin D and Your Health

Has your doctor tested for vitamin d deficiency?  It is a common factor in autoimmune diseases. 

There are over 200 non classic symptoms caused by Celiac Disease abd the malabsorption of vitamin and minerals that accompanies it; often mistaken for and unnecessarily treated with the side effects of those treatments.  The ultimate confirmation is how you do on a gluten free diet.  

 

[knitty kitty]

@NovemberNewbie2023,

Welcome to the forum.  Sorry to hear about what you are going through.  

It would be wise to complete testing for Celiac Disease if you want to have a healthy baby.

Antibodies for Celiac Disease are very specific to Celiac.  The Celiac antibodies only appear with exposure to gluten and disappear when no longer exposed to gluten, as your tests have shown.   If your first tTg test was a false positive caused by Hashimoto's, then the antibodies wouldn't have disappeared when gluten free.  

Hashimoto's and Celiac Disease are carried on some of the same genes.  Because they frequently occur together genetically, testing for Celiac Disease is a good idea.  

Celiac Disease and Autoimmune Thyroid Disease: The Two Peas in a Pod

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9312543/

 

Undiagnosed and untreated Celiac Disease causes fertility problems and miscarriages.   I've experienced this myself, as have many members on this forum.

Coeliac disease and unfavourable outcome of pregnancy

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1727862/

And...

Adverse pregnancy outcomes in women with celiac disease: a systematic review and meta-analysis

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756025/

 

"The Gold Standard" for diagnosis of Celiac Disease consists of an endoscopy after a gluten challenge.  Gluten Challenge Guidelines have been updated.  

Recommended intake of gluten should be increased to 10 grams of gluten per day for at least two weeks. Or longer.
While three grams of gluten will begin the immune response, ten grams of gluten is needed to get antibody levels up to where they can be measured in antibody tests and changes can be seen in the small intestine.  
Keep in mind that there are different amounts of gluten in different kinds of bread and gluten containing foods.  Pizza crust and breads that are thick and chewy contain more gluten than things like cake and cookies.  

References:

https://www.beyondceliac.org/celiac-disease/the-gluten-challenge/

And...

Evaluating Responses to Gluten Challenge: A Randomized, Double-Blind, 2-Dose Gluten Challenge Trial

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7878429/?report=reader

 "In our study, limited changes in Vh:celiac disease (villi height vs crypt depth - aka damage to the small intestine)  following 14-day challenge with 3 g of gluten were observed, in accordance with Sarna et al.  While the 3 g dose was sufficient to initiate an immune response, as detected by several biomarkers such as IL-2, the 10 g dose was required for enteropathy within the study time frame. Based on our data, we would suggest that gluten challenge should be conducted over longer durations and/or using doses of gluten of ≥ 3 g/day to ensure sufficient histological change can be induced."

 

Yes, taking time out to do the Gluten Challenge and endoscopy will postpone having a baby for a bit, but you will increase your chances of having a successful pregnancy and a healthy baby.

In undiagnosed Celiac Disease, antibodies mistakenly attack the lining of the small intestine resulting in the inability to absorb sufficient nutrients from the diet.  Nutritional deficiencies definitely affect the ability to get pregnant and carry to term.  Pregnancy will drain a mother's nutritional stores in order to provide the fetus with sufficient nutrients required for growth and development.  If your body already is experiencing nutritional deficiencies prior to conception, a pregnancy cannot be maintained. 

Do complete the gluten challenge and endoscopy to get a definitive diagnosis.  Focus on correcting nutritional deficiencies commonly found in untreated Celiac Disease.  Once your body is healthy, then look towards having a baby. 

Wish someone had explained this to me when I was undiagnosed and having miscarriages.  Hope this helps.

Further Reading...

https://thyroidpharmacist.com/articles/thiamine-and-thyroid-fatigue/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8451766/

 

[knitty kitty]

One more....

Efficacy of the Autoimmune Protocol Diet as Part of a Multi-disciplinary, Supported Lifestyle Intervention for Hashimoto’s Thyroiditis

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6592837/