Malabsorption

Alpha-1-antitrypsin (AAT) can be used as a marker for increased intestinal permeability of the intestinal mucosa (Leaky Gut Syndrome). AAT is a 52 Kd glycoprotein produced in the liver and by intestinal macrophages, monocytes and intestinal epithelial cells. It belongs to the group of acute phase proteins and represents one of the most important proteinase inhibitors in serum. Since the AAT is not split or resorbed in the intestine to any mentionable degree, it can be detected in stool by an increased permeability of the intestinal mucosa in the event of an inflammation. The increased detection of AAT in faeces occurs with increased permeability of the intestinal mucosa (leaky gut syndrome), e.g. in diseases of the group of allergic disorders, gluten intolerance (gluten sensitisation, coeliac disease or in non-tropical coeliac disease) as well as in enteral protein loss syndrome, bacterial or viral enterocolitides and in Crohn's disease/ulcerative colitis.

A test to determine calprotectin in the stool is also available. Calprotectin is a protein produced by neutrophilic granulocytes in inflammatory intestinal diseases. The determination of calprotectin in stool is used to detect inflammatory intestinal diseases, e.g. ulcerative colitis or Crohn's disease. It can also be used for monitoring bacterial or viral enterocolitides or intestinal neoplasia. The marker calprotectin also offers reliable differentiation between inflammation of the intestine and irritable bowel syndrome. While calprotectin values increase during inflammation, it is inconspicuous in patients with irritable bowel syndrome.