A patient experiences hypotension and shock after receiving 50 mL of Red Blood Cells. What additional testing should be performed?

When a patient experiences hypotension and shock shortly after receiving a blood transfusion, the foremost concern is the possibility of a transfusion reaction, particularly an acute hemolytic reaction or sepsis due to contaminated blood. Conducting a Gram stain and culture of the donor unit is essential in this scenario because it allows for the identification of any potential bacterial contamination in the blood product that could have caused the adverse effects.

Testing the donor unit through Gram stain can rapidly indicate the presence of bacteria, while culture can provide further confirmation and specific identification of pathogens. This is critical, as bacterial contamination can lead to life-threatening reactions. Antibiotic therapy may need to be initiated promptly if bacterial infection is suspected, and understanding the causative agent can guide treatment decisions.

The other options, while relevant to different circumstances in transfusion medicine, would not address the immediate need to determine whether the transfusion caused an infection or acute hemolysis. Lymphocytotoxicity tests for leukoagglutinins typically assess for antibodies against white blood cells, which would not be relevant to the acute symptoms presented. Plasma IgA levels are primarily related to allergic reactions but do not specifically assess for immediate hemolytic reactions or infections. Elution and antibody identification are used to investigate