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?

Choice A reason: Bilirubin assesses liver function, not kidneys. Cyclosporine’s nephrotoxicity affects glomerular filtration, not heme metabolism. Monitoring bilirubin is irrelevant for renal function in transplant clients, as it reflects hepatic or hemolytic processes, not kidney health or drug toxicity. Choice B reason: Alkaline phosphatase evaluates liver or bone health, not kidneys. Cyclosporine may cause hepatotoxicity, but renal monitoring is critical due to its nephrotoxic potential. Alkaline phosphatase does not reflect glomerular or tubular function, making it unsuitable for assessing renal impact. Choice C reason: Amylase measures pancreatic function, not kidneys. Cyclosporine’s nephrotoxicity affects renal filtration, not pancreatic enzymes. Monitoring amylase is irrelevant for kidney transplant clients, as it does not indicate renal impairment or cyclosporine’s toxic effects on kidney function. Choice D reason: Creatinine is a key renal function marker, reflecting glomerular filtration rate. Cyclosporine’s nephrotoxicity elevates creatinine, indicating kidney damage. Monitoring it with BUN ensures early detection of renal impairment, guiding dose adjustments to prevent further injury in transplant clients.