A screening colonoscopy, or preventative colonoscopy, is a procedure performed when there are no symptoms. A screening colonoscopy is performed generally at age 50 or over or if family/personal history of colon polyps or colon cancer.
If you are seeing a doctor for a GI related issue (blood in stool, diarrhea, etc.) and are being scheduled for a procedure, most likely you are not having a screening colonoscopy. Even though you may suspect that the bleeding is due to hemorrhoids, that is not always the case and would not be considered a screening colonoscopy.
A diagnostic colonoscopy is performed as a result of an abnormal sign, symptoms, or findings.
Positive hemoccult, Cologuard test (positive or negative), are considered screening tests, so your procedure would be considered a diagnostic procedure.