If you are undergoing a procedure with intravenous or general anesthesia, I require blood work as a matter of course. Not a year goes by when I do not have to make that phone call and suggest that a patient see a hematologist because the blood results are, unfortunately, outside normal limits. All women under 55 must also undergo a pregnancy test preoperatively; these webpages are full of questions from patients who learn that they are pregnant postoperatively and worry about the effects of anesthesia and pain medication on their unborn children. Safety should be first. If you are having a procedure under strictly local anesthesia, which is localized, then pretesting is not required. All of the ambulatory facilities and hospitals at which I operate require pretesting and, for patients over 45 or with underlying medical conditions, a clearance from the internist as well.