The nurse is caring for a client who is taking atorvastatin (Lipitor) to assist in lowering his LDL cholesterol. Which lab value must be routinely done with this medication to prevent complications?

A. Lung function tests are not relevant to atorvastatin therapy; they are more commonly associated with medications affecting the respiratory system. B. Platelet counts are not routinely monitored for patients on atorvastatin unless there are specific concerns related to bleeding or clotting. C. Liver function tests are critical for patients on atorvastatin because the medication can cause liver enzyme elevations, indicating potential hepatotoxicity. Routine monitoring ensures early detection of any liver complications. D. Hemoglobin levels are not specifically related to atorvastatin use and are generally monitored in contexts involving anemia or bleeding.