tTG stands for tissue transglutaminase, an enzyme normally present in the intestines. IgA stands for immunoglobulin A, an antibody produced by your body to help it fight off infections from viruses and bacteria, and other threats from toxins.
A positive tTG-IgA blood test indicates the body is creating antibodies to its own tissues, often in response to gluten ingestion.
Celiac Disease Frequently Asked Questions. University of Maryland Center for Celiac Research. Accessed Feb. 14, 2011.