I agree with the others posts, in our OR, you're likely to see pre op tests that need to be evaluated ahead of time, such as chest xray, ekg, basic blood work, etc.
Many times a social services consult may go along with that, to see what type of enviornment the pt is returning to, considering an alteration in mobility issue. Nurtrition and physical therapy, as well as home health too.
If the pt is healthy enough, somtimes they donate a unit or two of their own blood ahead of time. This has to be done far enough ahead so that they are not too anemic on surgery day.
The day of OR, likely you would see maybe some more basic blood work such as H and H, and urine looking for blood count, anticipating a blood loss in surgery, and the urine for possible infection, which many times cause the surgery to be postponed.
Good question,,,,lots to consider here. Mike