We will draw blood is the patient is receiving a transfusion. We put a comment on the results stating the patient was being transfused at the time of draw. We will draw a patient 15 minutes after transfusion. Here is the reference we used for our policy.
Elizalde, J.I., Clemente, J., Marin, J.L.,Panes, J., Aragon, B., Mas, A., Pique, J.M., Teres, J. "Early changes in hemoglobin and Hematocrit levels after packed red cell transfusion in patients with acute anemia." Transfusion Practice. Volume 37. (1997): 573.