Which test should be performed if a patient has a reaction to transfused plasma products?

Performing immunoglobulin levels is essential when a patient reacts to transfused plasma products because such reactions are often associated with an immune response to antibodies present in the transfused material. In cases of transfusion reactions, especially allergic or anaphylactic reactions, the measurement of immunoglobulin levels can help identify specific immunological factors, such as elevated levels of IgE, which can indicate an allergic response.

Additionally, the assessment of immunoglobulin levels may help in diagnosing underlying conditions, such as an immunodeficiency or antibody-mediated disorders, that could predispose the patient to adverse reactions to plasma products, including blood transfusions.

Other tests, while useful in different contexts, would not directly address the immediate concern of a transfusion reaction to plasma products. T-cell counts are more relevant for viral infections or certain immunological disorders but do not specifically help in assessing transfusion reactions. Hemoglobin levels are useful for evaluating anemia or the adequacy of a transfusion, but they do not provide insight into the cause of a reaction. Red cell enzymes are related to specific hemolytic anemias and are not relevant in the context of plasma product reactions.