Weak Positive Ttg Iga

[Sieben]

Hey everyone, first time poster.

I went in to the doc for chronic diarrhea and bloating. She ordered blood tests. My other symptoms include chronic fatigue and joint pain.

My TTG IgA came back 8.9 U/ml, a weak positive. A negative on their chart is < 4 U/ml. A positive is > 10 U/ml.I scored negative on the "ENDOMYSIAL IgA" at < 1:10. I haven't started a gluten-free diet yet for diagnostic reasons. I have an appointment with a GE in a few weeks.

So I'm wondering, how likely is it that I have celiac disease? What else could I have?

[MitziG]

You have it. It is like being "a little bit pregnant"

There are different factors that can influence the outcome of the test, and some celiacs show no antibodies on the test but their biopsies show damage.

I myself was a weak positive of 6, with levels below 4 being normal.

This after 30 years of being sick with celiac and undiagnosed. When they did the endoscopy the damage was so severe and very visible to the naked eye, so I was diagnosed on the spot, without even waiting for the pathology report. The doctor couldn't believe I didn't have raging diarrhea.

My main symptom was severe, debilitating fatigue and chronic canker sores. Some stomach issues but nothing major- I just thought it was normal to have spastic bowel movements a few times a month.

A false positive on the blood test is extremely rare- false negatives are very common howeever. I can't say why yours showed as only weakly positive, but please do ot disregard the seriousness of it, even if your doctor does! Many doctors are NOT well schooled in the ins and outs of celiac testing, and they do NOT understand what happens when the body is continually exposed to gluten.

Please spend time browsing this forum. You will learn more here than any doctor will tell you!

[Sieben]

Thanks for your reply MitziG.

I agree that the positive Ttg IgA test is significant. Alone, it would strongly suggest celiac disease. However, my negative test on the Endomysial IgA is suspicious. Both tests are supposed to have very high sensitivity/specificity for celiac disease, and yet I score positive on one and negative on the other. I don't know what the time-lag is between ingesting gluten and the relevant serum concentrations, but it had been about 20 hours since my last gluten at the time of the blood draw.

Are there conditions other than celiac disease that can raise Ttg IgA levels?

Regardless of the diagnosis, I plan to try gluten free for a couple of months after my meeting with the GE.

[squirmingitch]

You only quote 2 tests there. Were there more than that?

Here is the FULL celiac blood panel:

Anti-Gliadin (AGA) IgA

Anti-Gliadin (AGA) IgG

Anti-Endomysial (EMA) IgA

Anti-Tissue Transglutaminase (tTG) IgA

Deamidated Gliadin Peptide (DGP) IgA and IgG

Total Serum IgA

The DGP test was added recently to the full panel.

If you didn't get all those tests then you didn't really get tested for celiac disease.

[Sieben]

I didn't get any celiac disease specific tests other than the two I mentioned above. It was from a GP who was screening me for a variety of things. I have an appointment with a GE who will presumably run more tests.

But it's been reported in the literature that tTG IgA and EMA IgA are very highly sensitive and specific for celiac disease. But if I tested positive for the former and negative for the ladder, what else could it be? Is tTG elevated in all cases of gluten sensitivity?

[Skylark]

Are there conditions other than celiac disease that can raise Ttg IgA levels?

Specificity of TTG IgA in adults is maybe 95-98% (studies vary). Celiac is by far the most common reason for elevated TTG, particularly in people with celiac symptoms, which you have. Chronic diarrhea, bloating, and joint pain are all celiac symptoms.

Endomysial IgA does not have a terribly high sensitivity. It is around 75-80%. TTG IgA is the more sensitive of the two tests. The difference is that Endomysial IgA is specific for celiac.

Occasionally type 1 diabetes or autoimmune hepatitis can cause elevated TTG. TTG can also rarely appear in inflammatory bowel diseases like Crohn's and microscopic colitis. (Microscopic colitis can be gluten-caused; this may be a different expression of celiac disease.)

[Sieben]

Specificity of TTG IgA in adults is maybe 95-98% (studies vary). Celiac is by far the most common reason for elevated TTG, particularly in people with celiac symptoms, which you have. Chronic diarrhea, bloating, and joint pain are all celiac symptoms.

Endomysial IgA does not have a terribly high sensitivity. It is around 75-80%. TTG IgA is the more sensitive of the two tests. The difference is that Endomysial IgA is specific for celiac.

Occasionally type 1 diabetes or autoimmune hepatitis can cause elevated TTG. TTG can also rarely appear in inflammatory bowel diseases like Crohn's and microscopic colitis. (Microscopic colitis can be gluten-caused; this may be a different expression of celiac disease.)

Thanks Skylark.

I had considered Crohn's but it's much too rare to consider at the moment. DM 1 is probably ruled out by my blood sugar test coming back normal.

Autoimmune hepatitis sounds scary.

[Skylark]

Yeah, most of the stuff that could make TTG positive besides celiac is both rarer and much scarier than celiac. Sometimes it comes up with other autoimmune diseases - I think we have a board member whose doctor decided her elevated TTG on the gluten-free diet might have been from Hashimoto's. I also don't associate Crohn's with joint pain, while some people with celiac have both GI and joint trouble.

By the way, some people get substantial relief from joint pain by eliminating all nightshade vegetables from their diet. Nightshades are tomato, potato, eggplant, sweet and hot peppers of all types, paprika, tomatillo, and pimento. It worked wonders for a friend of mine and she's shouting it from the rooftops now.

[Sieben]

According to this study, the EMA-IgA should be at least as sensitive/specific as the tTG IgA antibodies. So it's confusing that I test positive for one and negative for the other.

I'll keep the nightshade vegetables idea on the backburner

[Skylark]

According to this study, the EMA-IgA should be at least as sensitive/specific as the tTG IgA antibodies. So it's confusing that I test positive for one and negative for the other.

I'll keep the nightshade vegetables idea on the backburner

I don't know what study you picked up but I typically see 75%-80% sensitivity on anti-EMA in studies. A really good diagnostic lab might get 85%. Remember that anti-EMA is hand-processed and read so there is a lot of diagnostic lab variability.

In the real world rather than studies it's RARE that people test positive to every celiac test. Spend a little time browsing this part of the message board and you'll see what I mean. Even in studies if you're reading current literature you'll see that at least two celiac tests are recommended (TTG-IgA and DGP-IgG) with endoscopy if either is positive. You only seem to get a super-clear diagnosis when the autoimmunity is horrible and your villi are pretty much destroyed.