The normal value of glutamyl transferase in liver function is usually between 11 and 50 U/L. If it is higher than 50 U/L, it is considered to be elevated. If the elevation is occasional, it is usually not necessary to pay attention to it and continue to be observed. However, if the patient has elevated alkaline phosphatase and total bilirubin, especially direct bilirubin, in addition to elevated glutamyl transferase, and the total bilirubin is more than 34.2 μmol/L or higher, the patient should be considered to have biliary infarction. In this case, the patient is considered to have biliary obstruction, which is the cause of obstructive jaundice in patients with biliary obstruction. Patients need to actively improve the relevant examination, perform ultrasound examination of the upper abdomen or MRCP water imaging of the biliary tract to see if the obstruction is caused by the biliary tract or due to tumor compression. If necessary, ERCP should be performed to remove the stone or stent the bile duct or drain the nasobiliary duct under ERCP.