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Test Preparation?

lyndsay

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lyndsay Newbie
lyndsay
Posted

hello. i'm at work and have already taken up way too much time skimming through the topics, so i thought i would just ask with the risk of repeating an already discussed topic. hope you don't mind...

i was in the middle of getting my gi problems diagnosed and was scheduled for a colonoscopy and biopsy of the stomach, but had to reschedule b/c it was the week i was getting married (my nerves (and calendar!!) just couldn't handle it!)

since the doctor told me about a month ago that i might be celiac (or is it "have celiac"? i don't know the terminology yet...), i've tried to avoid gluten and have felt better (and feel awful when i eat it!). i want to reschedule the tests, though, just to make sure and to see if there's anything else going on down there. what kind of preparations do i need to make? my husband thinks that i should start eating foods with gluten again or else the results will be off since my body isn't having a reaction. is he right? if so, how long should i eat it before getting tested? my doctor told me not to change my diet before the colonoscopy, but after being off of gluten and feeling so much better, i feel like my stomach gets tight just in anticipation of the pain of eating gluten!! any advice?

is there anything else i need to know about the tests?

thanks~

lyndsay

Every breath is a mercy.

-Andrew Peterson

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Smunkeemom Enthusiast
Smunkeemom
Posted

your husband is right, you have to be on gluten for the tests to show up (unless you just had a LOT of damage and it's still not healed)

I think the rule is 3 months with the equivelent of 4 slices of bread a day.

Rachel--24 Collaborator
Rachel--24
Posted

Your doctor and husband are right to say keep eating gluten before the tests. Going gluten free....even for a short time can skew the reults. It is recommended that you eat gluten for about 3 months prior to testing. You will want to eat normal amounts of gluten during that time. A restricted diet can give false negatives.

That being said, how important are the tests to you? If you notice improvement in symptoms you probably already have your answer. If you need the tests to convince you then you need to be eating gluten.

mouse Enthusiast
mouse
Posted

Welcome to the board. If you decide that you don't want to put yourself thru being sick again, you can make a list of all the things that have improved or are better. You can present this to your doctor and ask if he would say you were gluten intolerant. Then you have a diagnosis. Either Celiac or gluten intolerance requires being totally gluten free for life. It is only a name difference. The blood tests can come back with a false postive. I know that I could not now delibertly eat gluten for 3 months for a test. It would not be worth the pain and misery I would go thru. But, I have to tell you that there are some tough members who have done just that to get an official diagnosis. This is easy for me to say as I have an official one. Each must make up there own mind what they can live with. Good luck in whatever choice you make.

Smunkeemom Enthusiast
Smunkeemom
Posted
Welcome to the board. If you decide that you don't want to put yourself thru being sick again, you can make a list of all the things that have improved or are better. You can present this to your doctor and ask if he would say you were gluten intolerant. Then you have a diagnosis. Either Celiac or gluten intolerance requires being totally gluten free for life. It is only a name difference. The blood tests can come back with a false postive. I know that I could not now delibertly eat gluten for 3 months for a test. It would not be worth the pain and misery I would go thru. But, I have to tell you that there are some tough members who have done just that to get an official diagnosis. This is easy for me to say as I have an official one. Each must make up there own mind what they can live with. Good luck in whatever choice you make.

I think she means a false negative. You can't get a false positive, only a false neg.

(bold added by me)

lyndsay Newbie
lyndsay
Posted
  • Author
I think she means a false negative. You can't get a false positive, only a false neg.

(bold added by me)

or, i was wondering if armetta might have meant that my blood tests that said my celiac levels were questionable could be wrong, and maybe i'm not gluten intolerant afterall?

thanks for all the advice. i think i would love to go through the tests in the hope that they would come back negative, which would mean that i wouldn't have to go through the hardship of keeping clear of gluten - it's everywhere!!! and almost impossible to avoid unless you just eat salads the rest of your life. i'm just going to call my doctor and talk to her about it.

DrMom Apprentice
DrMom
Posted

You actually statistically, CAN get a false positive. That would mean you have something when in reality, you do not.

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Smunkeemom Enthusiast
Smunkeemom
Posted
You actually statistically, CAN get a false positive. That would mean you have something when in reality, you do not.

I was actually told by a few doctors (different settings) that you can not get a false positive on a blood test for celiac, since it's looking for antibodies and you body would not produce those antibodies without reason.

mouse Enthusiast
mouse
Posted

Oops :blink: . I MEANT a false negative as you cannot get a false positive. I have been really sick with severe allergies and I am a real dummy right now. Sorry about that, but am glad that people have corrected my mistake. Maybe I should stay away from posting until my breathing gets better :blink: .

And yes, you can get a false positive on some tests, but not Celiac as it was explained in the prior posting by Smunkeemom.

Wandering Hermit Contributor
Wandering Hermit
Posted

As someone who performs difficult measurements for a living (I'm an engineer in a high tech company) I can assure you that no test is perfect. I don't care what you are trying to measure, you can always screw it up.

As for the contention that a positive blood test means that you have celiac with 100% certainty, I refer you to this document on this very site: LINK

If this notion was actually true, then the Positive Predictive Value of the tests would be 100% across the board. It is not.

As for me, I had only one of 3 blood tests come up positive for celiac disease, and it was IgG AGA. According to the document linked above, the probability that I have celiac disease based on that test alone is between 42% and 76%.

Now this linked article says nothing about tTG. My tTG was normal. I have seen the specificity of tTG quoted to be in the 90% range, so based on that test alone, one could conclude that I don't have celiac disease with about a 90% probability. Which stat is correct? Don't know, it is a gray area.

If you are lucky, all the tests in the panel will be pegged at either the high end or the low end, and then you can state your conclusion with great confidence. But in a case like mine, one cannot conclude squat from the blood tests.

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