A nurse is preparing to administer packed red blood cells (PRBCs) to a client with anemia. The unit of blood on hand is O negative, but the client has type A positive blood. Which action should the nurse take?

A. Premedicating with diphenhydramine is an intervention used to prevent allergic transfusion reactions, such as urticaria or pruritus, in patients with a known history of sensitivity. It does not address ABO compatibility or the safety of the specific blood type being administered. Since O negative blood is the universal donor, no allergic reaction related to type mismatch is anticipated in this scenario. B. Notifying the provider and blood bank is unnecessary because there is no error in the blood type provided. O negative blood lacks A, B, and Rh antigens on the erythrocyte surface, making it safe for a client with A positive blood. Routine communication is essential, but alerting these departments for a compatible transfusion would be an inappropriate use of clinical resources. C. Extending the infusion time to 5 hours is clinically contraindicated, as blood components must be fully administered within 4 hours to prevent bacterial proliferation. Prolonging the transfusion beyond this safety window increases the risk of septic reactions and degrades the quality of the red cells. Standard protocols require completion within 2 to 4 hours to maintain the integrity of the PRBCs. D. The nurse should administer the blood as ordered because O negative is the universal donor and is fully compatible with an A positive recipient. The recipient's antibodies will not react with the O negative donor cells because those cells lack the A, B, and Rh antigens. This is a safe and standard pharmacological practice when the specific blood type is unavailable or in emergency clinical situations.