A nurse is preparing to administer a blood transfusion to a client. Which of the following actions should the nurse take to prevent a transfusion reaction?

Choice A reason: Checking the client’s temperature hourly monitors for transfusion reactions but does not prevent them. Fever may indicate a reaction, but prevention relies on ensuring blood compatibility and proper administration. Monitoring is a reactive measure, not a proactive step to avoid mismatches or errors causing hemolytic or febrile reactions. Choice B reason: Verifying the client’s identity and blood type with another nurse is critical to prevent transfusion reactions. Mismatched blood types cause hemolytic reactions due to antibody-mediated destruction of donor red cells. Double-checking ensures the correct blood unit is administered, preventing life-threatening immunological responses and ensuring patient safety during transfusion. Choice C reason: Administering diphenhydramine may prevent mild allergic reactions to blood transfusions, such as hives, but it does not address severe hemolytic reactions caused by ABO incompatibility. It is not routinely given prophylactically unless the client has a history of allergic reactions, making it less critical than verifying blood compatibility. Choice D reason: Infusing blood over 6 hours increases the risk of bacterial growth and hemolysis in the blood unit, as transfusions should typically be completed within 4 hours. Prolonged infusion does not prevent reactions and may cause complications, making it an incorrect action for ensuring safe transfusion practices.