Preop or OR RNs

Any preop or OR Rns out there? I continue to search for info. from other hospitals regarding policy for pregnancy tests of preoperative pts. Also, do any of you continue to do preop lab testing on children other than the AM of the procedure? We cont. to have 2 ped. docs. that insist we bring these children in at least the day before surgery for lab tests. I'm talking routine H & H , possibly ppt/aptt for tonsillectomy. All my research indicates this is not necessary, that these should be drawn am of surgery along with their IV start.. I need your help - any written policies out there to help me?