In this immunocatalytic assay for alpha-amylase (EC 22.214.171.124) of pancreatic origin, a highly specific monoclonal antibody coupled to plastic beads is used to extract pancreatic amylase from samples, leaving salivary amylase in solution. The catalytic activity of the bound pancreatic amylase is then determined with blocked p-nitrophenyl maltoheptaoside as substrate. The method shows no cross-reactivity with salivary amylase, analytical recovery is 89-109% for pancreatic amylase, and interassay imprecision is 7.1-7.7%. We used the method to determine pancreatic amylase in serum and urine from healthy controls and different patient groups. The reference intervals for 34 supposedly healthy controls were: serum, 10-48 U/L (mean 27 U/L); urine, less than 20-435 U/L (mean 104 U/L). Results by the present assay correlated well with a salivary amylase inhibition assay (Boehringer Mannheim). We conclude that the described immunocatalytic assay is clinically useful for detecting increased activities of pancreatic amylase in serum and urine.