CA199 is one of the digestive tract tumor markers, and elevated CA199 can see gastroenterology or oncology. CA199, i.e. glycan antigen 199, is mostly distributed in the pancreas, gastrointestinal, liver and gallbladder of normal human body, with the normal value ranging from 0 to 37 U/mL. It is one of the common tumor markers for digestive tract tumors, and it can be used to check pancreatic cancer, gallbladder cancer, gastric cancer, hepatocellular carcinoma, colorectal cancer and so on. When CA199 is mildly elevated, it is of little significance and may be caused by inflammation or tumor, which requires microscopic observation to distinguish between inflammation and tumor, and then follow-up observation. When CA199 is obviously elevated, it is necessary to be alert to the occurrence of digestive tract tumors, which can be clarified by abdominal enhanced CT, gastroscopy, enteroscopy and other auxiliary examinations. It is recommended that the patient go to the hospital in time to improve the relevant examinations, make a clear diagnosis, and actively treat the disease.