TGM2 and microscopic colitis: Serum tissue transglutaminase immunoglobulin A (TTG-IgA) was elevated in all four of these patients who had a confirmatory duodenal biopsy for CD, ranging from 28-186 units/mL with a mean of 90.75 units/mL (reference range 0-19 units/mL). Eosinophilic colitis, eosinophilic duodenitis, microscopic colitis, and portal gastropathy were diagnosed in the remaining patients at one patient each. All patients with abnormal biopsies underwent directed treatment of their specific GI disorder based on endoscopic and biopsy findings.