Amylase - a hydrolytic enzyme, decomposes starch and glycogen to maltose. Amylase is formed predominantly in the salivary glands and pancreas, then enters respectively into the oral cavity or the lumen of the duodenum and participates in the digestion of carbohydrates. In the serum, pancreatic and salivary isozymes of amylase are isolated. Significantly lower amylase activity is also experienced by organs such as the ovaries, fallopian tubes, the small and large intestine, and the liver. Therefore, the level of amylase can be increased in a number of diseases that have a similar pattern with acute pancreatitis (acute appendicitis, peritonitis, perforated gastric ulcer, intestinal obstruction, cholecystitis, mesenteric thrombosis, pheochromocytoma, diabetic acidosis, after operations for heart defects, drugsetc.). The increase in amylase activity is, in most cases, reactive. In acute pancreatitis, the activity of blood and urine amylase increases 10-30 times in 4-6 hours after the onset of the disease, reaches a maximum after 12-24 hours, then decreases rapidly and comes to normal on the 2-6th day. The level of increase in serum amylase does not correlate with the severity of pancreatitis. Amylase can form large complexes with immunoglobulins and other plasma proteins (macroamylase), so it does not pass through the renal glomeruli. At the same time, its content in the serum increases, in the urine normal activity of amylase is observed. In pancreatic cancer, the activity of amylase is increased slightly or remains normal, therefore, for the diagnosis of pancreatic cancer the test is poorly informative.