Misc Instructions

NOTES: 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.

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. If serology is negative and suspicion for CD remains strong, intestinal biopsy may still be warranted to establish a diagnosis.

In patients with dermatitis herpetiformis (DH), uneven antibody patterns are possible. Concurrent CD reflexive panel testing and immunobullous disease panel testing are preferred to assess for DH.