CA199 is a sugar antigen with a normal value of less than 37.00 U/ml. When CA199 is mildly elevated, it can be seen in some benign diseases. CA199 is a tumor marker, but its specificity is not high. When CA199 is elevated to a large extent, it indicates that the patient has a higher possibility of developing tumors in the liver, gallbladder or pancreas. However, it is not possible to directly identify a tumor by CA199 alone, and CT and MRI examinations of the liver, gallbladder or pancreas should be completed in a timely manner, and local pathological tissue biopsies such as guidance and puncture biopsy can be used to make a definite diagnosis of the disease. When malignant tumors of the liver, gallbladder or pancreas are present, in addition to abnormal elevations in CA199, elevations in CA242 may also be seen, and the relevant tests should be completed promptly. In addition, mild elevation of CA199 is also associated with gynecological inflammation, as well as biliary system and digestive system diseases, such as polyps, cysts and other benign masses, or the presence of pelvic inflammatory disease, chronic pancreatitis, gallbladder stones, hepatitis, cirrhosis and other diseases can also lead to elevated CA199. Some pregnant women, or long-term smokers or drinkers, may also have elevated CA199, which is a false-positive result and can be rechecked again to confirm the diagnosis. It is recommended that patients with elevated CA199 should go to the hospital in time to improve relevant examinations and under the guidance of the doctor for treatment. If the tumor is diagnosed, surgery should be performed in a timely manner, and chemotherapy and radiotherapy can also be applied to control the development of the disease to avoid deterioration.