A nurse is reviewing the medical record of a client who is receiving vancomycin daily. The nurse should review which of the following laboratory results prior to administering the next dose?

A. Thyroid-stimulating hormone level: TSH levels are used to assess thyroid function and are not affected by vancomycin therapy. Monitoring TSH is unrelated to safe administration of this antibiotic. B. Blood glucose level: Blood glucose monitoring is important for clients with diabetes or receiving medications that affect glucose, but it is not directly relevant to vancomycin dosing or toxicity. C. Total iron-binding count: Total iron-binding capacity reflects iron status and is unrelated to vancomycin therapy. It does not influence dosing or safety considerations for this antibiotic. D. BUN level: Vancomycin is nephrotoxic, and kidney function must be monitored to prevent accumulation and toxicity. Blood urea nitrogen (BUN) provides an indicator of renal function, and reviewing it prior to the next dose helps ensure safe administration.