Final answer:
The nurse should include in discharge teaching the need for frequent laboratory blood testing for an older adult patient who had a mitral valve replacement with a mechanical valve and is taking warfarin.
Step-by-step explanation:
The nurse should include in discharge teaching the need for frequent laboratory blood testing for an older adult patient who had a mitral valve replacement with a mechanical valve and is taking warfarin. Warfarin is an anticoagulant medication that helps prevent blood clot formation, but it requires regular monitoring of blood levels to ensure the correct dosage. Laboratory blood testing, such as the international normalized ratio (INR), is used to assess the effectiveness and safety of warfarin therapy. It helps determine if the patient's blood is clotting properly or if the dosage needs adjustment.