The reagents, measurement methods, and instruments used for Glycoantigen 199 testing vary from hospital to hospital, and the normal value range may vary, generally between 0-37,000 U/L. Glycoantigen 199 is an oligosaccharide tumor-associated antigen, a new tumor marker. It is usually present in serum as salivary mucin and is distributed at the epithelium of the normal fetal pancreas, gallbladder, liver, intestines and normal adult pancreas and bile ducts. It is a gastrointestinal tumor-associated antigen present in the circulation. Mild elevation of glycoantigen 199 can be seen in inflammation of the digestive tract, and significant elevation can be seen in digestive tract tumors, which is clinically beneficial to the diagnosis of pancreatic cancer, colorectal and rectal cancer. Therefore, it is recommended that patients cooperate with doctors to improve the standardized examination, to avoid delaying the diagnosis, resulting in aggravation of the condition.