A nurse is caring for a client who has a prescription for furosemide. Which of the following laboratory tests should the nurse monitor?

A. Prothrombin time: PT measures blood clotting and is primarily monitored in clients taking anticoagulants such as warfarin. Furosemide does not significantly affect coagulation. B. Thyroid stimulating hormone: TSH is monitored in clients with thyroid disorders. Furosemide has no direct effect on thyroid function, making this test unnecessary for routine monitoring. C. Arterial blood gases: ABGs assess respiratory and metabolic status. While severe fluid or electrolyte imbalances could indirectly affect ABGs, routine monitoring is not required solely for furosemide therapy. D. Blood urea nitrogen: Furosemide is a loop diuretic that increases renal excretion of water and electrolytes. Monitoring BUN helps assess renal function and hydration status, as excessive diuresis can lead to azotemia or dehydration.