A nurse is preparing to administer a scheduled dose of warfarin to a client. Which of the following laboratory tests should the nurse review prior to administration?

A. PTT (partial thromboplastin time) is used to monitor heparin therapy, not warfarin. It measures the intrinsic pathway of coagulation. B. PT (prothrombin time) is the correct test to review before administering warfarin. PT measures the extrinsic pathway of coagulation and is used to calculate the INR (International Normalized Ratio), which helps monitor and adjust warfarin dosage to ensure therapeutic levels and prevent complications. C. Total iron-binding capacity is a measure of iron status and is not relevant to warfarin therapy. D. WBC (white blood cell count) is important for assessing infection or immune status but is not directly related to monitoring warfarin therapy.