Alpha-1-Antitrypsin, Random, Feces

Casandra

Casandra Test Code MC37332Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID A1AFCPT Code 82103

Alpha-1-Antitrypsin, Random, Feces

Clinical Use

Use

Alpha-1-antitrypsin (AAT) is a 54-kDa glycoprotein that is resistant to degradation by digestive enzymes and is used as an endogenous marker for the presence of blood proteins in the intestinal tract. It helps in diagnosing protein-losing enteropathies when used in conjunction with serum AAT levels as a part of AAT clearance studies. Conditions such as regional enteritis, sprue, Whipple's disease, gastric carcinoma, allergic enteropathy, intestinal lymphangiectasia, constrictive pericarditis, congenital hypogammaglobulinemia, and iron deficiency anemia can be evaluated with this test. Increased fecal excretion of AAT indicates protein loss, especially in intestinal diseases.

Special Instructions

Prefer using a 24-hour fecal specimen and serum determinations to normalize serum AAT concentration variability and the variability in random fecal AAT concentrations. In the absence of full collections, the fecal concentration of AAT can act as a surrogate marker. Ensure the absence of gastric AAT loss to validate test results. If gastric AAT loss is suspected, performing the test while patient is under acid-suppressive medication is recommended.

Limitations

The test is limited in its capacity to serve as a reliable indicator if the gastric loss of AAT is suspected, particularly in conditions like Menetrier's disease, due to AAT's susceptibility to low pH, where it is rapidly destroyed. Urine contamination, particularly from patients with kidney failure, may also affect the fecal AAT concentration. It's crucial to ensure proper sample collection to avoid misleading results.

Test Details

New York Approved