A nurse is caring for a client who will have blood sampling for a serum creatinine level and asks what this test shows. Which of the following responses should the nurse make?

A. "You'll have to ask your doctor" is inappropriate; nurses are responsible for providing accurate patient education within their scope of practice. B. "We'll find out if any medications, such as steroids..." is misleading; while medications may affect kidney function, the serum creatinine test specifically reflects kidney filtration ability, not drug levels. C. "This test will tell your doctor how your kidneys are functioning" is the best response, as serum creatinine is a key indicator of renal function. D. "This test will tell if you have severe renal impairment..." is too limited; while elevated creatinine may suggest severe impairment, it is used more broadly to assess overall kidney function.