Glycosylated chain antigen 15-3 value of 20U/ml is within the normal range and does not require special treatment. Glycosylated antigen 15-3, or glycoantigen 15-3, abbreviated CA15-3, is a tumor marker.CA15-3 is a breast-associated antigen, but is not very specific, and is seen to be expressed in a variety of tumor cells. The reference value range is generally 0-35U/ml, 20U/ml is within the normal range and does not require special treatment. If the value of CA15-3 is high, there is no special clinical significance, the common reason is that the patient has chronic inflammation, such as chronic gastritis, chronic cholecystitis and so on. Only when the value continues to rise or rises several times or even more than ten times the normal value, it suggests that there may be malignant tumors in the body.