INTRODUCTION Immunohaematology examinations are usually prescribed preoperatively according to more or less standardized protocols. We wanted to assess the relevance of these protocols on the basis of factual data: an overview of the rate of transfusions carried out as part of surgery within the HCL in 2009. STUDY DESIGN The list of patients operated in 2009 in the HCL (IPOP by Cristalnet) has been combined with the list of patients transfused in the same time period (CTS server, Inlog). The percentage of patients transfused during the stay, and the percentage of patients transfused on the day of the intervention itself were determined for each type of surgery. The study focused on 13,571 patients affected by 44 surgeries. PATIENTS AND METHODS Six hundred and thirty-three patients were transfused, 45% of them the day of the intervention. The risk of needing to carry out a transfusion depends on the risk to the patient and surgery. For example, the total hip arthroplasty transfusion risk is 11.9% when it's programmed against 37.8% in emergency surgery. The transfusion risk of knee arthroscopies, osteosynthesis of wrist fracture, carpal canal surgeries and of appendectomies, thyroidectomies, herna repair surgeries are below 0.5%. The transfusion risk of colectomy is 18.1%. Thus, new recommendations for good clinical practices on the relevance of settled surgery-preoperative immunohematologic exams can be established. CONCLUSION The emergency degree of the transfusion must be taken into account for such recommendation. Each hospital should perform its own cartography to justify its own protocols.