Contradictory blood test results

[TheBay]

I am on a gluten-containing diet and got some confusing blood test results. I haven't found anyone else with such a high DGP Ab IgG. I'm seeing an internist soon and waiting on a gastroenterology referral still. My results are in bold. Anyone know what this might mean?

Deamidated Gliadin peptide Ab IgG HI 165.3 <12.0 U/mL POSITIVE

Tissue Transglutaminase Ab IgA <0.5 <12.0 U/mL NEGATIVE

IgA (Serum Protein) 0.83 0.54-4.17 g/L

[trents]

May we ask why you had this bloodwork done? We're you having symptoms that would suggest to you that you might have a gluten-related medical condition?

Edited July 8, 2021 by trents

[TheBay]

I have been dealing with iron deficiency anemia for 2 years. Taking iron supplements hasn’t helped at all and I am tired all the time. In addition, I get infections easily and have gas and irregular bowel movements. My doctor ordered a celiac test to check if that was why I wasn’t absorbing iron. 

[trents]

Your total IGA is on the low side, though technically and clinically not considered out of spec. This might be helpful in understanding the antibody tests that can be run to check for celiac disease: https://celiac.org/about-celiac-disease/screening-and-diagnosis/screening/

Deamidated gliadin peptide (DGP IgA and IgG): This test can be used to further screen for celiac disease in individuals with IgA deficiency, which affects 2-3% of patients with celiac disease, or people who test negative for tTg or EMA antibodies. IgA deficiency in a patient may be indicative of other diseases that may cause villus atrophy, such as giardiasis, small-bowel bacterial overgrowth (SIBO) or common variable immunodeficiency (CVID). 

The TTG-IGA test is the most common one run by physicians and considered to be the "go to" antibody test if the doc will only run a single test. However, recent research has cast doubt on it's reliability. It is considered to be one of the more "specific" antibody tests for celiac disease but it is not particularly sensitive, meaning it can miss many who actually do have celiac disease, particularly when total IGA is on the low side.

The gold standard for diagnosing celiac disease is the endoscopy with biopsy of the small bowel lining to check for damaged villi. I would consider pushing your doc to order the scoping to either confirm or rule out celiac disease. The other option is for you to commit to the gluten free diet and see if you improve. But realize if you do that before all testing is complete, either blood antibody testing or scoping with biopsy, it will render the tests invalid.

Having said all that, your symptoms scream of celiac disease.

[Scott Adams]

Your DGP test indicates that you have celiac disease, and that combined with your low iron issue and GI issues seem to confirm this. Be sure to keep eating gluten until all your tests are completed. It's possible that your doctor will want to do an endoscopy to confirm this, but it's also possible that they will diagnose you based on your over 10x the celiac cut off in your DPG test result.

[TheBay]

Thank you both for your response! I had similar thoughts. I read a handful of articles that said DGP was predictive, but also found some that said it wasn’t. I agree that my symptoms and test seem to indicate celiac. My doctor said the specialist will order a biopsy, so I should find out for sure. I’m going to continue eating gluten until things are sorted. 

[Scott Adams]

Let us know how things turn out!

[TheBay]

On 7/8/2021 at 12:15 PM, trents said:

Your total IGA is on the low side, though technically and clinically not considered out of spec. This might be helpful in understanding the antibody tests that can be run to check for celiac disease: https://celiac.org/about-celiac-disease/screening-and-diagnosis/screening/

Deamidated gliadin peptide (DGP IgA and IgG): This test can be used to further screen for celiac disease in individuals with IgA deficiency, which affects 2-3% of patients with celiac disease, or people who test negative for tTg or EMA antibodies. IgA deficiency in a patient may be indicative of other diseases that may cause villus atrophy, such as giardiasis, small-bowel bacterial overgrowth (SIBO) or common variable immunodeficiency (CVID). 

The TTG-IGA test is the most common one run by physicians and considered to be the "go to" antibody test if the doc will only run a single test. However, recent research has cast doubt on it's reliability. It is considered to be one of the more "specific" antibody tests for celiac disease but it is not particularly sensitive, meaning it can miss many who actually do have celiac disease, particularly when total IGA is on the low side.

The gold standard for diagnosing celiac disease is the endoscopy with biopsy of the small bowel lining to check for damaged villi. I would consider pushing your doc to order the scoping to either confirm or rule out celiac disease. The other option is for you to commit to the gluten free diet and see if you improve. But realize if you do that before all testing is complete, either blood antibody testing or scoping with biopsy, it will render the tests invalid.

Having said all that, your symptoms scream of celiac disease.

Just saw an internist. They said I don’t have the symptoms of celiac (despite having fatigue, weight loss, diarrhea, gas, anemia) and that they prefer to just test TTG, not DGP. I insisted on a biopsy because of the mixed results and so I will find out for sure. It was good to hear responses like yours before going in, so I felt confident enough to advocate for the test. 

[trents]

Obviously, that internist has little knowledge of celiac disease. Your symptoms are among the most common of celiac disease.

[TheBay]

Here's an update for others who had similar blood test results to mine. I had an endoscopy and colonoscopy and they took biopsies. The biopsies show no evidence of celiac disease. They showed mild inflammation. I have since had an iron infusion which largely resolved the tiredness, but no explanation for why I was anemic to begin with.

[trents]

Pernicious anemia is a fairly common cause for iron deficiency anemia. It's caused by lack of something called "intrinsic factor" which results in the inability to absorb B12, a necessary vitamin in the chain of biochemical transactions necessary to assimilate iron. You might get that looked into.

Edited August 26, 2021 by trents

[TheBay]

5 hours ago, trents said:

Pernicious anemia is a fairly common cause for iron deficiency anemia. It's cause by lack of something called "intrinsic factor" which results in the inability to absorb B12, a necessary vitamin in the chain of biochemical transactions necessary to assimilate iron. You might get that looked into.

Thanks for your response! I will definitely look into that.