A nurse is assessing a client who is prescribed spironolactone. Which of the following laboratory values should the nurse monitor for this client?

Rationale: A. Serum potassium: Spironolactone is a potassium-sparing diuretic that can cause hyperkalemia. Monitoring serum potassium is essential to detect elevated levels early and prevent cardiac complications. B. Platelet count: Spironolactone does not significantly affect platelet production or function, so routine monitoring of platelets is not indicated for this medication. C. Urine ketones: Ketone monitoring is relevant for clients with uncontrolled diabetes or ketosis, but it is not related to spironolactone therapy. D. Total bilirubin: Bilirubin levels are used to assess liver function, which is not directly affected by spironolactone in most clients, so routine monitoring is not necessary unless the client has underlying hepatic disease.