Fecal alpha-1 antitrypsin (AAT) is a biomarker that can be measured in stool samples to assess certain gastrointestinal conditions. It is a marker for protein loss in the intestines and can be used to evaluate gastrointestinal disorders that affect the integrity of the gut lining.
Alpha-1 antitrypsin (AAT) is a protein produced by the liver and released into the bloodstream. It plays a crucial role in protecting the lungs and various other organs from damage caused by enzymes like neutrophil elastase. A deficiency in AAT can lead to lung and liver problems.
Intestinal Protein Loss: Fecal AAT is a marker for increased protein loss from the intestines. Elevated levels of fecal AAT can indicate that proteins are escaping from the gastrointestinal tract into the stool.
Gastrointestinal Disorders: Conditions that may lead to increased fecal AAT levels include inflammatory bowel disease (IBD), celiac disease, protein-losing enteropathies, and other disorders that cause damage to the intestinal lining.
Assessment of Gut Integrity: Measuring fecal AAT can help assess the integrity of the gut barrier. When the intestinal lining is damaged, it allows proteins, including AAT, to leak into the stool.
Fecal AAT testing can be used as part of the diagnostic workup for individuals with gastrointestinal symptoms, particularly in cases where there is suspicion of protein-losing enteropathies or severe intestinal inflammation. Elevated levels of fecal AAT can indicate a problem with intestinal permeability and protein loss. The interpretation of the test results should be done in the context of the patient's clinical presentation and other diagnostic tests.
If alpha-1 antitrypsin is elevated in the absence of a positive occult blood test, increased loss of plasma proteins from the bowel is present. If occult blood is positive, the alpha-1 antitrypsin is at least partly derived from blood loss, but a coexistent Protein-losing enteropathy cannot be excluded.
See also: Alpha-1 Antitrypsin, Clearance
