A nurse is caring for a client who is scheduled for a blood sampling for a serum creatinine level. The client asks the nurse, "What is the purpose for this test? Which of the following responses should the nurse give?

"This test will inform your provider if you have an infection."

"This test will inform your provider if you have a thyroid disorder."

"This test will inform your provider if you are anemic."

"This test will inform your provider how your kidneys are functioning."