Which client assessment is essential prior to a transfusion?

Assessing for allergies is crucial prior to a blood transfusion because allergic reactions can occur due to the immune system's response to foreign antigens present in the transfused blood product. By determining whether the patient has a history of allergies, particularly to blood products, healthcare providers can anticipate and mitigate potential adverse reactions. Allergies can range from mild to severe, and knowledge of a patient's sensitization to certain plasma proteins or blood components allows for proper premedication protocols or the selection of compatible blood products. Therefore, confirming any known allergies informs the healthcare team and directs their approach to managing the transfusion safely.

While checking vital signs, reviewing medication history, and inspecting the injection site are all important components of patient assessment and care, they do not specifically address the direct risk of allergic reactions associated with blood transfusions. Vital signs help monitor the patient's overall stability during the procedure, while medication history could inform potential drug interactions, and inspection of the injection site ensures proper administration, but it is the assessment for allergies that is essential for preventing immediate and potentially life-threatening complications related to transfusion.