Fecal clearance of alpha1-antitrypsin with lansoprazole can detect protein-losing gastropathy

Detecting plasma protein loss from the stomach is quite difficult by measuring fecal alpha1-AT clearance because alpha1-AT is rapidly destroyed in the gastric juice at values below pH 3. We examined protein loss from the stomach using fecal alpha1-AT clearance with lansoprazole, a proton pump inhibitor. A 38-year-old Japanese male presented with hypoproteinemia (total serum protein: 4.4 g/dl). Abdominal scintigraphy using technetium-99m-labeled albumin revealed distinct radioactivity accumulation in the small intestine. It strongly suggested excessive protein loss to the gastrointestinal tract. Although, regular fecal alpha1-AT clearance was within the normal range (<13 ml/day), the fecal alpha1-AT clearance with the administration of lansoprazole was 80.5 ml/day. The results indicated that this method using lansoprazole is simple and useful for detecting protein-losing gastropathy.