What is Urine Amylase?
Amylase is a group of pancreatic and salivary isoenzymes that hydrolyse starch and glycogen into smaller sugars. Pancreatic amylase circulates at low concentrations and, being a relatively small protein (approximately 50 kDa), is freely filtered at the glomerulus and partially reabsorbed by the proximal tubule. When circulating amylase rises — through pancreatic injury, salivary inflammation, or impaired renal clearance — urinary excretion increases, though the magnitude and timing lag behind serum changes. A 24-hour collection integrates this urinary excretion, smoothing diurnal fluctuations and providing total daily output.