CA19-9

CA19-9 is the common term for carbohydrate antigen
sialyl Lewis a and it is also called cancer antigen 19-9.
It is a protein that exists on the surface of certain cancer cells,
and normal results are less than 37 U/mL. A high amount of CA
19-9 is most often caused by pancreatic cancer, but it can be elevated
in many other cancers and other diseases and it is not
useful for people who are Lewis antigen-negative.