Tissue Transglutaminase Antibody, IgA With Reflex to Endomysial Antibody, IgA by IFA

In individuals who produce sufficient total IgA, the most sensitive and specific serologic test for celiac disease (CD) diagnosis is tissue transglutaminase (tTG) IgA. In individuals who are IgA deficient, tTG IgG and deamidated gliadin peptide (DGP) IgG antibody testing is recommended.

Reflexive panel testing is preferred to screen for CD.

Some patients may have positive tTG IgA results but negative endomysial antibody (EMA) IgA and/or DGP IgA results, which may indicate early disease or be associated with false positivity. Close clinical correlation with continued testing may be indicated in patients who have a family history or increased risk for CD. If serology is negative and suspicion for CD remains strong, intestinal biopsy may still be warranted to establish a diagnosis.

All serologic tests used to diagnose CD should be performed while the patient is on a gluten-containing diet. Upon initiation of a gluten-free diet, antibody titers decline in treatment-responsive patients, and the time frame to normalize titers varies by case.

Specimens are screened using tTG IgA by PMAT. If tTG IgA is 5.00 FLU or greater, then EMA IgA by IFA testing will be added. Additional charges apply. All EMA IgA by IFA testing is titered to endpoint.