Amylase assay is generally used to examine the following diseases: 1. Clinically, amylase assay is mainly used as an aid to diagnosis in acute abdomen and suspected acute pancreatitis. Amylase is mainly secreted by the salivary glands and the pancreas. In mumps, especially in acute pancreatitis, amylase will flow back into the blood and the amylase activity in the blood will increase significantly. If it exceeds 500 U/L its diagnostic significance, and if it reaches 350 U/L, acute pancreatitis should be highly suspected, but it should be noted that blood should not be taken immediately after abdominal pain, but usually only after about 8 hours, otherwise a false negative result will be obtained. The positive rate of amylase in pancreatitis is only about 75%, and the measured value is not normal, because the degree of amylase increase is not necessarily proportional to the severity of inflammation, such as edematous pancreatitis, amylase can reach a very high degree, while in some necrotizing pancreatitis, due to the destruction of a large number of pancreatic tissues, blood amylase instead of increasing; 2, when the digestive system diseases, blood amylase will be mild to moderate In some necrotizing pancreatitis, due to the massive destruction of pancreatic tissue, the blood amylase is not increased. However, the elevation is low, generally below 500 U/L. 3. In macroamylasemia, serum amylase will be significantly elevated, but urinary amylase is normal. In addition, familial hyperamylasemia, asymptomatic elevation of blood amylase can occur. 4. Many malignant tumors can cause elevation of serum amylase, or even substantial elevation, most commonly ovarian cancer, lung cancer and multiple myeloma. Ectopic synthesis of tumor tissue is the cause of this phenomenon.