Ttg Test Seems To Be Dependent Upon Lab

[jajus100]

In my never ending desire to understand all these tests more, I was suprised by the following article: https://www.celiac.com/st_prod.html?p_prodid=1070

Based on most of my readings, I thought the tTG test to be pretty specific and sensitive. According to this article, it seems to be very lab dependent. They did the blood test at the same time they had the biopsy confirm results. This is what they found:

The average tTG sensitivity overall was 71% with a specificity of 67%. In patients with total villous atrophy sensitivity was as high as 92%, and in those with only partial villous atrophy it was as low as 38%. One of the four laboratories tested samples from 48 of the patients and their sensitivity was only 51%, while the specificity was 100%.

The final conclusion of the article:

According to these results it appears that tTG testing—at least outside of the clinical study setting—may not be accurate, and its accuracy depends heavily on which lab is used.

I am getting more confused than ever after reading this.