Sorry to tell you that the answer to both (does Crohn's show up in blood work or CT scan) is NO. My son was just diagnosed with it after they cut into him to remove his appendix. He had blood tests and a CT scan, but they didn't detect the Crohn's until they cut him open. I believe the only sure way to know is to have an iliemoscopy (spelling?). Trust the signals your body is sending you. Don't stop until you get a diagnosis. Go to a gastroenterologist. Good luck.