Bob had a CA 19 blood test about two weeks ago. The result was 650, or thereabouts. Our Oncologist called for another test to determine whether to start chemo or if Bob had a chance to gain more strength first. We got the result back today. It was 315. Bob has not received any chemo or radiation. The only treatment he has are metal stents to drain the bile ducts. Does anyone know what would be the reason for the drop. The nurse left the information on the answering machine or I would have asked. Many thanks in advance.