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Amylase in blood and urine
Last reviewed: 05.07.2025
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Reference values (norm) of alpha amylase activity: in blood serum - 25-220 IU/l; in urine - 10-490 IU/l.
Alpha amylase belongs to a group of hydrolases that catalyze the hydrolysis of polysaccharides, including starch and glycogen, into simple mono- and disaccharides. The pancreas and salivary glands are the richest in amylase. Amylase is secreted into the blood mainly from these organs. Human blood plasma contains two types of α-amylase: pancreatic (beta-type), produced by the pancreas, and salivary (S-type), produced by the salivary glands.
Under physiological conditions, the activity of this enzyme in the blood serum is 40% represented by pancreatic amylase, 60% by salivary amylase.
Determination of alpha-amylase activity is important in diagnosing pancreatic diseases. An increase in alpha-amylase activity in the blood serum by 2 times or more should be regarded as a symptom of pancreatic damage. Mild hyperamylasemia gives grounds to suspect pancreatic pathology, but is sometimes possible with diseases of other organs.
The beta-type of alpha amylase is excreted mainly in urine, which is considered one of the reasons why urine amylase is more informative than blood serum in terms of assessing the functional state of the pancreas. It is believed that 65% of the enzyme activity in urine is due to pancreatic amylase. This explains the fact that in acute pancreatitis it increases in blood serum (up to 89%) and especially in urine (up to 92%), without changing the amylase indices of the salivary glands.
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