A nurse is reviewing the BUN result of a client who is taking cyclosporine following a kidney transplant. Which of the following laboratory studies should the nurse recognize as another renal function study that should be monitored?

Rationale: A. Creatinine: Serum creatinine is a key indicator of renal function. Cyclosporine is nephrotoxic, so monitoring both BUN and creatinine helps detect early signs of kidney impairment or transplant rejection. B. Alkaline phosphatase: This enzyme primarily reflects liver and bone activity, not renal function. It is not routinely used to evaluate kidney status. C. Bilirubin: Bilirubin levels are used to assess liver function and hemolytic disorders, not kidney function. D. Amylase: Amylase is an enzyme related to pancreatic function and used to diagnose pancreatitis, not renal impairment.