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Reasons for an increase in pancreatic amylase in the blood and urine
Last reviewed: 23.04.2024
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Reference values (norm) of activity of pancreatic alpha amylase: in the blood serum - 30-55% of total amylase (average 43%) or 17-115 IU / l; in urine, 60-70% of the total amylase (an average of 65%).
In the serum, up to 3 isoenzymes of alpha-amylase are detected, the main ones being beta and S-types, that is, pancreatic and salivary glands. Pancreatic amylase is better excreted in the urine than the isoenzyme of the salivary glands. An increase in the activity of salivary amylase is noted with stomatitis, Parkinsonism, a decrease in mental agitation or depression, with an anacid state of gastric secretion.
The main value of determining the beta-type alpha amylase is that the increase in its activity is highly specific for pancreatic diseases. Pancreatic alpha amylase increases with acute pancreatitis. The activity of total amylase in this case is increased due to the pancreatic fraction. The diagnostic sensitivity of the pancreatic fraction of amylase in the blood serum for acute pancreatitis is 92%, specificity - 85%.
Determination of the activity of the pancreatic alpha amylase fraction is especially important in chronic pancreatitis in patients with normal levels of total amylase. In patients with chronic pancreatitis pancreatic amylase is 75-80% of total blood amylase. Increase in pancreatic amylase indicates an exacerbation of chronic pancreatitis, and a decrease in exocrine pancreatic insufficiency with atrophy of acinar tissue and organ fibrosis in patients suffering from this disease for a long time.
The activity of pancreatic alpha amylase, in addition to the diagnosis of acute pancreatitis, is also determined after surgery on the abdominal organs for the purpose of early diagnosis of the complication development - postoperative pancreatitis. Pancreatic alpha amylase in the urine rises with acute pancreatitis, and constitutes the main part of the total amylase, as it is excreted better in the urine than the salivary fraction.
The activity of the pancreatic fraction of alpha amylase, unlike the general one, does not increase with parotitis, diabetic ketoacidosis, lung cancer, acute gynecological diseases. However, the test may be false-positive in other diseases that do not affect the pancreas.
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