I would reference you to the NYSDOH Guidelines for Transfusion Committees, 3rd edition, 2006, page 2, B. It states the following: "The committee may establish guidelines for reservation of blood and for typing and screening pf patients scheduled for commonly performed elective surgical procedures for which blood transfusion may be anticipated. At a minimum, the committee must establish guidelines for each surgical procedure performed more than five times in the preceding calendar year, and set the maximum number of hours that crossmatch blood will be held on reserve." Hope this helps!