Help With My Blood Test Results

[Nizzy]

My test results came in today and I'm a bit confused.

TTG Antibody, IgA: <1 Interpretation: Negative

TTG Antibody, IgG: 10.0 U/ml

I'm already scheduled for a biopsy because the nurse said it is a good sign of celiac, but could someone please explain what this means - the nurse didn't explain it very well?

I have read a few things that say some people don't produce the IgA antibody but could produce the IgG antibody instead.

Has anyone had similar results? If so, did you test positive in your biopsy?

Thanks!

[JoshB]

Unfortunately different labs use different methods and reporting ranges, so absolute numbers like that aren't very helpful. As I understand it "IgA" indicates gluten antibodies. These do not prove or disprove celiac trouble, they are just suggestive. You can have false positives for a number of reasons, and you can have a false negative if your immune system is doing strange things. "IgG" tracks gluten associated antibodies against the yourself. Generally a positive test here indicates celiac disease. A negative IgG doesn't necessarily mean anything as the test is not all that sensitive.

Hard to say without knowing the ranges on your test how "positive" your IgG was.

I rejected doing the biopsy as it seemed to me that they'd already tested positive in a way that was known to be accurate. I figure the biopsy is expensive, dangerous, time-consuming, and not very accurate at all, so what's the point? But... I had very high positives on all the blood work. If my blood work wasn't clear, I'd probably want a second way to test.

Ask your doctor for clarification. He should be able to tell you what your tests mean and why he wants to do the endoscopy. If he's not real clear I wouldn't be afraid to ask for a referral to a specialist.

[Roda]

Some people have an IgA deficiency which will render any IgA based testing invalid. Did they do a total IgA?

[Nizzy]

Some people have an IgA deficiency which will render any IgA based testing invalid. Did they do a total IgA?

I am unsure if they did a total IgA. I'm pretty new to this and when I went into the doctor I barely knew what celiac disease was. I know they took a bunch of different blood tests - my thyroid, ect. And I was told by the nurse that everything looked normal minus the TTG IgG test.

Then I recieved a short note from my doctor in the mail that said exactly above and that I needed to schedule a f/u with him.

I should call and ask them to send my total blood work sent to me...Maybe it would look a little different?

[pain*in*my*gut]

I am unsure if they did a total IgA. I'm pretty new to this and when I went into the doctor I barely knew what celiac disease was. I know they took a bunch of different blood tests - my thyroid, ect. And I was told by the nurse that everything looked normal minus the TTG IgG test.

Then I recieved a short note from my doctor in the mail that said exactly above and that I needed to schedule a f/u with him.

I should call and ask them to send my total blood work sent to me...Maybe it would look a little different?

You could request all of your test results (it's good to have all of the info). Regardless, you need to have further investigation (like a scope) to rule in/out celiac. You tested positive for an antibody to an enzyme that is being made in response to gluten that causes tissue damage to your small intestines (tTG). This test is sensitive, but it's not very specific, meaning that it can be positive due to other conditions like diabetes, heart failure, Crohn's disease and liver disease.

As far as antibody classes goes, there are 5 types that everybody has as part of their immune system: IgG, IgA, IgM, IgE, and IgD. Each class of antibodies is associated with different immune responses in the body. When testing for Celiac Disease, we are primarily looking for antibodies of the IgA class, because they are typically associated with the mucosa of the gastrointestinal tract. The problem with just testing tTG IgA class when doing a Celiac screen, is that IgA antibodies can be decreased in malabsorbtion disorders like Celiac! In which case the tTG (IgA) would be negative, and the Celiac disease diagnosis would be missed entirely. That is why we do a total IgA measurement, to make sure that the patient is not IgA deficient. If they are, then the IgG antibody class is tested against tTG. The IgG antibody is the most abundant class of antibodies in the body, and the patient would have to be severely malnourished to give a "false" negative IgG result for Celiac.

It looks like your doctor ordered the Celiac screen that tests for both IgG and IgA tTG antibodies. The lab my doc uses only does the IgA class, but then also does a total IgA to make sure there is no deficiency. It really depends on the lab and the doctor, as there really is no set standard for what exactly should be in a Celiac screen (unfortunately).

Sorry if this got WAY over the top! I am a med tech and I worked in an immunology lab for 9 years. If anybody really wants to go crazy, here is a link about antibodies (scroll to the last part of the article, where it talks about the 5 types and what they are associated with). WARNING, your head may explode!

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