Lab results fluctuations

[elm1214]

Hi, I just had a question about how often lab results fluctuate. My daughter was diagnosed with Celiac last summer. Her tTG IgA was 9.2 (<7 negative, 7-10 equivocal, >10 positive) and she had a positive biopsy. 

The rest of our family was tested after her diagnosis. My husband and my sister’s tTG IgA labs came back as <2 (0-3 negative, 4-10 weak positive, >10 positive), and my other two kids tTG labs were 0.1 and 0.2. 

My total IgA was normal, and my tTG IgA came back at 2 (<3 is negative). I was just curious because my labs were higher than everyone else, am I at a higher risk of developing Celiac? Or do the tTG IgA numbers fluctuate from 0-3 often? Thanks for any help!

[RMJ]

Were your husband’s, sister’s and your tests run at the same lab?  One can only compare tests made by the same manufacturer because the units for these tests are arbitrary, not absolute.

That said, if at the same lab, I wouldn’t call<2 and 2 different.  If the exact same sample is run multiple times the results can easily be a little different each time. The <2 could be almost 2 or almost 0.  If a lab reports a result as < a number it is because that number is the limit of quantitation - results below that are not able to be stated with numerical accuracy, although they are below that limit.

I would guess that your kid’s tests were run at a different lab?  Because it doesn’t make sense otherwise that one result would be <2 and another 0.1 or 0.2.

[Scott Adams]

I think the fact that you had elevated levels could mean that you are in the non-celiac gluten sensitive category, and you may want to consider trying a gluten-free diet.

Also, were you eating ~2 slices of wheat bread worth of gluten daily for 6-8 weeks before the test? If not, the results could be lower than they would have been if you had followed the protocol for celiac blood tests.