Cancer antigen 19-9(CA19-9) is a glycoprotein commonly associated with malignant tumors such as pancreatic, colorectal, stomach, liver, and lung cancers. The determination of CA19-9 can be used for tumor diagnosis, efficacy observation and recurrence monitoring.

The normal reference value of CA19-9 is ≤37U/ml. When levels of CA19-9 exceed the normal range, it may indicate the presence of a tumor or other disease. However, the level of CA19-9 can also be affected by other factors, such as inflammation, infection, liver disease, etc. Therefore, the presence of tumors cannot be determined solely by the level of CA19-9, and a comprehensive judgment should be made in combination with other examination results.