The reference value of ca199 is <37,000 U/L (CLIA, RIA, ELISA), which can vary depending on the testing unit, and it is recommended to refer to the actual lab report form. ca199 is clinically known as glycan antigen 199, which belongs to oligosaccharides tumor-associated antigen and is a tumor marker. The substance exists in serum in the form of mucin and is mainly distributed in the pancreas, bile duct epithelium and other parts of the body. Therefore, it is often used in the clinic as a marker for initial screening of malignant tumors in the digestive tract. If the test result shows that ca199 is higher than normal, it suggests that one may suffer from malignant tumors of the digestive tract, such as pancreatic cancer, gallbladder cancer, bile duct cancer, gastric cancer, colorectal cancer, etc. However, some non-cancerous factors can also cause ca199 to be elevated. However, some non-cancerous factors can also cause elevated ca199. At this time, we should further improve the ultrasound of liver, gallbladder, pancreas and spleen, abdominal CT, MRI and other related examinations to clarify the specific causes of elevated ca199.