What finding indicates that a client is experiencing an allergic reaction during a blood transfusion?

An individual experiencing an allergic reaction during a blood transfusion typically presents with urticaria, which is characterized by raised, itchy welts on the skin. Urticaria occurs as a response to allergens triggering the release of histamine and other inflammatory mediators from mast cells, leading to localized swelling and redness.

Fever, while it can be a symptom of a transfusion reaction, is more commonly associated with febrile non-hemolytic reactions rather than specifically indicating an allergic response. Chills may occur during various types of transfusion reactions, including febrile or hemolytic responses, but do not specifically suggest an allergic reaction. Hypotension can be a sign of severe transfusion reactions, including allergic or anaphylactic reactions, but it is not a defining symptom of an allergic reaction alone. Therefore, the presence of urticaria is a more direct indicator of an allergic response during blood transfusions.