Blood biochemistry of primary biliary cholangitis (PBC) is characterized by elevated serum alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT), and immunology is characterized by positive anti-mitochondrial antibodies (AMA) and elevated serum immunoglobulin M (IgM). 1. Blood biochemistry: mainly characterized by marked elevation of ALP and/or GGT, which may be accompanied by mild to moderate elevation of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). As the disease progresses, serum bilirubin (mainly direct bilirubin) gradually rises and serum albumin gradually decreases. 2. Immunologic examination (1) Anti-mitochondrial antibody (AMA), serum AMA is a specific marker for diagnosing PBC, especially AMA-M2 subtype, the sensitivity and specificity of diagnosing this disease is as high as 90%~95%. However, positive AMAs can also be seen in a variety of intrahepatic and extrahepatic diseases, such as autoimmune hepatitis, chronic hepatitis C, acute liver failure due to various causes, systemic lupus erythematosus, desiccation syndrome, chronic bacterial infections, and so on, and even in healthy people. (2) Antinuclear antibody (ANA), which is positive in about 50% of PBC patients, is another important marker for the diagnosis of PBC when AMA is negative. Diagnostic criteria The diagnosis of PBC requires a comprehensive evaluation based on biochemical, immunologic, imaging and histologic examinations.