Before colon and rectal surgery, a variety of laboratory examinations, including chest X-ray, electrocardiogram (EKG), complete blood count (CBC), chemistries, coagulation parameters, are routinely required. If you are anemic or there is risk for significant blood loss, a sample of your blood will be held at the blood bank to expedite replacement blood in your type if transfusion becomes necessary. A computed tomography (CT) or computerized axial tomography (CAT) scan of the abdomen and pelvis may be ordered by your physician. This study can help to evaluate the local or metastatic (spread) of any cancer. For rectal cancers, a transrectal ultrasound, which determines the depth of a tumor and possible lymph node involvement, can also help in determining the best treatment options.