Diagnosis of protein-losing enteropathy by gastrointestinal clearance of alpha1-antitrypsin.

Alpha1-antitrypsin was assessed, in 10 patients with protein-losing enteropathy and 13 control subjects, as an endogenous marker of plasma-protein loss into the gastrointestinal tract. Both faecal alpha1-A.T. concentrations and faecal alpha1-A.T. clearance were significantly higher in patients than in controls. Wtih clearance there was no overlap between the groups. Over 10 days the normal gastrointestinal clearance of alpha1-A.T. was 3.07 +/- 2.25 (S.D.) ml/day. Measurement of alpha1-A.T. clearance is easy and requires no radioisotopes.