Final answer:
Registered Nurses should monitor for increased international normalized ratio (INR) when a patient is taking warfarin, as it measures the blood's clotting tendency and guides therapeutic management.
Step-by-step explanation:
When taking warfarin, an anticoagulant medication, healthcare professionals, including Registered Nurses (RN), should closely monitor for an increased international normalized ratio (INR). Warfarin's therapeutic effect is measured by the INR, which provides a standardized value for the blood's tendency to clot. Monitoring INR is crucial because an elevated INR indicates that blood is clotting more slowly than usual, increasing the risk for bleeding complications. Conversely, a lower than therapeutic INR means the blood may clot too easily, lacking the desired anticoagulant effect. It is important not to confuse the need for INR monitoring with other conditions such as elevated blood pressure, decreased platelet count, or reduced serum glucose levels, which are not directly related to the therapeutic monitoring of Warfarin.