A nurse is preparing to administer plasmapheresis to a client diagnosed with systemic lupus erythematosus (SLE). Which of the following assessments should the nurse prioritize most before beginning the procedure?

Assessing the client's pain level and management plan.

Inquiring about the client's dietary intake over the past 24 hours.

Checking the client's history of allergies to contrast media.

Evaluating the results of the client's most recent complete blood count (CBC).