I had read on this site and my doctors seem to agree that CA19-9 is not a test that locks in that you have cancer. There are other things that can cause high numbers like infection. I had low BP 70/40 and fever. CA19-9 was 1303. A scan is what show if for sure you have cancer, or it is something else. In my case the CT scan show an inflamed and infected ascending large colon. After IV antibiotics and other treatments I could remember, and my BP was back up in normal range. I had sepsis and blood culture showed infection. Weeks post hospital stay for this my CA 19-9 was back down to 55. To me this indicates that even extremely high CA 19-9 numbers can be caused something other than cancer. Best wishes to all.