Can You Get A False Positive For Celiac (Ttg)?

[chisket]

Hi there,

Thanks to all of you who have been so generous with your responses to my previous posts. I initally logged on because my 11 year old was tested for celiac...the tTg reference range was >19.9 and she tested 73...then confirmed with a scope/biopsy.

My husband, older daughter and I had a celiac panel taken and my husband and I tested negative. My older daughter, 12, tested low positive, tTg 21.

My primary care doc said she had celiac based on a sibling with it and a low positive, then called back to say he spoke to the ped. gastro doc and it was suggested my daughter take a 30 day gluten challenge. If the test results were the same or higher, then he would do a scope to confirm celiac.

Well, just got the bloodwork back and she came in at 7.2! This blew me away because I thought I read here that you can get get false negatives but rarely do you get a false positive. Does anyone have any advice as to next steps? My major concern is that my daughter is 12 and on the cusp of puberty...she's rather short in stature. I'm afraid if I wait too long to figure this out, she'll find out she's celiac too late and won't be able to catch up in growth.

My instinct is to put her on a six month gluten free diet and see what happens, but wondered if anyone out there has any insights as to the inconsistent bloodtests and/or next steps?

Many thanks again for all of your help. You guys rock.

Mary

[Roda]

First off did she have the test ran at the same lab? Different labs can have different reference ranges. For example: my youngest son tested low positive(16) also on his ttg in Nov. 2010. The reference range for that lab was greater than 15 positive. The lab where I had mine done has a reference range of greater than 19 positive. I put my son (he is 6.5) on a gluten free diet and did not put him through a scope. I did a gluten challenge 4.5 months later with bad results. I know he has celiac even though his number was low positive and because I am diagnosed and his reaction to the gluten challenge. The number really doesn't correlate well with symptoms. He was tested two years prior to this also after I was diagnosed and his value was 2, so indeed he had an increase. We are dealing now with dental issues from his untreated celiac with his permanant teeth.

My oldest son on the other hand (he is 10.5) and has tested negative three times on the blood work. He does have symptoms that warrent further testing. He is short in stature, has constipation/bloating issues and stomach pains. He goes tomorrow for a GI consult. I'm hoping to get him scoped based on his symptoms my youngest son and I having celiac and his allergist's recommendation. Of course he could be gluten intolerent and never show on blood work or one of the few who have negative blood work and positive biopsy. I want to do the scope since he is symptomatic and negative blood work. Regardless of the biopsy results, or if doctor won't scope him, I will trial him gluten free and challenge him down the road. Of course if the biopsy is positive then gluten free for good.

[T.H.]

Was your child gluten free and THEN went on a 30 day challenge? If that's the case, the 30 day challenge may not have been long enough. A number of people here have had to consume gluten for 6-12 weeks before they had enough damage to test positive for the disease. 30 days really isn't enough for a good challenge, IF your child has been gluten-free for a while.

Oh, and the ped gastro sounds fairly ignorant. 1 in 22 people 'with no symptoms' who are 1 degree separated from a celiac (sibling, parent, child) will also have celiac disease. Add in a positive test, no matter how 'low positive,' and it's even less likely your child is NOT celiac.

Also, if your child wasn't gluten-free for very long, I do recall reading here at one point - cannot remember from who - that a celiac.com's member's doctor had a theory about that.

In this doctor's opinion, some celiacs would have lower tests after they were on gluten for a while because their bodies were getting so run down that they couldn't MAKE the proper antibodies.

As I understand it, he came to this conclusion because he would have patients on gluten who would have low readings, or low positives, and then he'd have them go gluten free. When they had healed for a while, he'd do a short gluten challenge and suddenly, their numbers would go through the roof.

So, if this theory is valid - and I don't believe it's every been tested - it might explain the numbers, too.

My instinct is to put her on a six month gluten free diet and see what happens, but wondered if anyone out there has any insights as to the inconsistent bloodtests and/or next steps?

That is pretty much what I'd do, although I'd go for a year. That's what we did with my son. Daughter was positive, son was negative but also short, bloated tummy, etc... On a gluten-free diet (plus eliminating a couple food allergies), their symptoms resolved. At 1 year, we trialed gluten for a week with our son. He reacted. Mildly, but it was very clear, so we've kept him gluten-free ever since. There are 4 diagnosed celiacs in my family now, so I feel comfortable that even if he is not celiac, he's having trouble with gluten and his chances of developing celiac disease are high enough that he should be learning the diet anyway.

Good thing gluten isn't a required nutrient in our diet! :-D

[come dance with me]

Our doctor told me that it's like a pregnancy test in that a false positive is highly unlikely but a false negative can easily happen for a number of reasons.