Assessment of Renal Function Pre-CT Scan

A nurse is preparing a patient for a computed tomography (CT) scan with iodine-based contrast. The patient has a history of renal impairment and is currently taking metformin.

Before administering the contrast, the nurse knows they must assess the patient's renal function.

Fill in the blank with the crucial laboratory test that should be reviewed to determine the patient's renal status before the procedure: The nurse should check the serum __________ levels, as elevated levels increase the risk of contrast-induced nephropathy.