Amylase, Urine

Amylase, Urine (alpha-amylase; diastase) supports the diagnostic evaluation of abdominal pain when acute or chronic pancreatitis is considered, typically alongside serum lipase. Urinary values contribute to the differential diagnosis of pancreatic disease and assist in assessing pancreatic pseudocyst or suspected ductal compromise, as urine concentrations can remain increased after serum amylase has normalized. It may also be used to track treatment in pancreatic malignancy and to evaluate pancreatic duct patency following biliary stone interventions.

Amylase is one of the principal exocrine enzymes of the pancreas, complementing lipase, which hydrolyzes fats, and proteases, which hydrolyze proteins; amylase hydrolyzes complex carbohydrates. These enzymes are secreted into pancreatic juice and delivered through the pancreatic duct into the duodenum to facilitate digestion. Under physiologic conditions, small amounts of amylase circulate in blood from turnover of pancreatic and salivary tissues and are filtered and excreted in urine. Pancreatic injury, including pancreatitis, or mechanical obstruction of the pancreatic duct by a stone or tumor, increases the amount of amylase entering the bloodstream and, subsequently, the urine. Extra-pancreatic production also occurs in smaller quantities in the ovaries, intestine, bronchi, and skeletal muscle.