Celiac.com 10/16/2008 - When faced with possible cases of celiac disease, it is known that testing for tissue transglutaminase (TTG) antibodies and newly developed deamidated gliadin peptide (DGP) antibodies offers greater accuracy than testing for native gliadin antibodies. But what is the best overall test for TTG and DGP?

A research team recently set out to compare multiplex immunoassay (MIA) testing for antibodies against enzyme-linked immunosorbent assay (ELISA) testing for antibodies in biopsy-proven celiac patients and control subjects, and to determine the helpfulness of using the two tests in combination for making diagnosis of celiac disease.

The research team was made up of doctors S. Rashtak, M. W. Ettore, H. A. Homburger & J. A. Murray. Doctors Rashtak and Murray are with the Mayo Clinic in Rochester, Minnesota.

The team compared sensitivity, specificity and accuracy of MIA and ELISA testing methods for TTG and DGP antibodies in 92 adults with untreated celiac disease, and 124 healthy control subjects. For every test, except TTG IgG, the results showed strong agreement and a significant correlation between the results of MIA and ELISA methods (j > 0.8, r > 0.7). For TTG IgG, both showed low sensitivity (MIA-13.0% vs. ELISA-28.3%), high specificity (MIA-100.0% vs. ELISA-96.8%), and about the same levels of overall accuracy (MIA-63.0% vs. ELISA-67.6%).

They found no significant differences between diagnosis accuracy made using the MIA method compared to diagnosis made using ELISA, or between either of those against a combination of the two methods.

Compared to using either test alone, using both tests together made for a slight increase in overall test sensitivity where any one of the tests was positive, and an increase in specificity when all tests were positive.

The team determined that MIA testing for antibodies is as accurate as ELISA for celiac disease diagnosis and offers practical advantages over ELISA method. MIA testing measures multiple antibodies simultaneously, provides a complete antibody phenotype, and offers a quicker turnaround time and lower cost. They further noted that carefully targeted combination testing can help identify patients who require intestinal biopsy, which may reduce unnecessary biopsies.

Aliment Pharmacol Ther 28, 805–813

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