Objective:To investigate the role of Golgi protein 73(GP73)in the diagnosis of primary biliary cholangitis(PBC)and its association with disease progression and therapeutic efficacy monitoring.Methods:Serum samples were collected from 70 PBC pa-tients,36 patients with liver diseases other than autoimmune liver disease(non-AILD group),and 40 healthy controls(HC group),and ELISA was used to measure the serum level of GP73.For the inpatients with PBC,serum samples were collected before and after treat-ment to measure GP73.Results:There was a significant difference in the distribution of serum GP73 concentration between the PBC group,the non-AILD group,and the HC group(P<0.001),and the receiver operating characteristic(ROC)curve showed that GP73 had an area under the ROC curve of 0.839 in the diagnosis of PBC.Serum GP73 level was positively correlated with aspartate amino-transferase(AST)(r=0.337,P=0.009),alkaline phosphatase(ALP)(r=0.380,P=0.003),total bilirubin(r=0.330,P=0.010),and direct bilirubin(r=0.371,P=0.004),while it was negatively correlated with prothrombin activity(r=-0.329,P=0.036)and cholinesterase(r=-0.518,P<0.001).The PBC patients with liver cirrhosis had a significantly higher serum GP73 level than those without liver cirrhosis(P=0.002).There was no significant difference in GP73 content between the patients with positive anti-mitochondrial antibodies-M2,anti-BCOADC-E2PDC-E2 OGDC-E2 antibodies,and anti-SPl00 antibodies and those with negative antibodies.The PBC patients had significant reductions in the serum levels of AST,ALP,gamma-glutamyl transpeptidase,and GP73 after liver-protecting treatment and improvement in cholestasis(P<0.05).Conclusion:GP73 plays an important role in the diagnosis,disease progression,and efficacy monitoring of PBC and is expected to become a potential disease marker for PBC.