Bilirubin levels in biochemistry tests are the main source of bilirubin. Bilirubin can be categorized into direct bilirubin and indirect bilirubin, which add up to total bilirubin. If the patient has biliary sludge, the bilirubin level will be elevated in the biochemistry report. If direct bilirubin is predominantly elevated, with direct bilirubin accounting for more than 50% of the total bilirubin, it is important to consider whether surgical factors are responsible for the cholestasis or obstructive jaundice. Cholestasis is usually caused by an obstruction of the bile ducts, which makes it difficult for bile to be discharged, resulting in bile refluxing into the bloodstream, which in turn causes an elevation of total bilirubin in the blood. Cholestasis can be categorized into intrahepatic cholestasis and extrahepatic cholestasis. Intrahepatic cholestasis can be caused by autoimmune liver disease, viral hepatitis, drug-induced liver damage, etc. Extrahepatic cholestasis can be caused by choledochal stones, biliary and pancreatic tumors and other causes. Patients with cholestasis symptoms should further improve the abdominal CT, pancreaticobiliary MRI, autoimmune liver antibody, hepatitis virus antibody and other tests to further clarify the diagnosis.