A nurse is reviewing laboratory results for a client who is taking warfarin. Which of the following laboratory tests determines if the dose of medication is within the recommended target range?
Explanation & Rationale
Rationale: A. INR: The International Normalized Ratio (INR) is used to monitor the effectiveness and safety of warfarin therapy. It standardizes prothrombin time results, allowing clinicians to determine whether the client’s anticoagulation is within the therapeutic range to prevent clotting without causing excessive bleeding. B. Factor VIII: Factor VIII is a clotting factor assessed in hemophilia or other coagulation disorders. It is not used to monitor warfarin therapy and does not indicate the therapeutic effect of anticoagulation. C. Bleeding time: Bleeding time measures platelet function and vascular integrity, but it does not assess the anticoagulant effect of warfarin. It is unrelated to monitoring warfarin dosing. D. aPTT: Activated partial thromboplastin time (aPTT) is used to monitor heparin therapy, not warfarin. It does not provide information about the client’s warfarin anticoagulation status.