Does Elevated CA19-9 Level Indicate Underlying Medical Issues?

Hi, My daughter's two ovaries have been taken out because of Poly cystic ovary condition, yasmin was prescribed by her doctor so that she will have a regular period.
Her latest blood test return a normal CA 12-5 but her CA19-9 is a bit high its in the 300+, a cat scan was ordered but nothing was found.
Is there something there that we should investigate more or is there any test that should be done to find out about why her CA19-9 is a bit high?
Thanks You for your reply
Max