Which laboratory value is monitored to assess anticoagulation in patients taking warfarin?

Which laboratory value is monitored to assess anticoagulation in patients taking warfarin?

• A. INR
• B. aPTT
• C. Glucose
• D. Potassium

Answer: (A)

Warfarin changes the way the body forms certain clotting factors, so the test that reflects how anticoagulated the blood is should measure the overall clotting tendency affected by these factors. Prothrombin time was the traditional measure, but PT values vary a lot depending on the lab’s reagent. The INR standardizes this result so you can reliably compare values across different labs and adjust warfarin dosing to stay within a safe therapeutic range. That standardized metric is what clinicians rely on to gauge anticoagulation in patients taking warfarin. Note that aPTT is used to monitor heparin therapy, not warfarin, so it doesn’t indicate warfarin-related anticoagulation. Glucose and potassium are not used to monitor anticoagulation.

Warfarin changes the way the body forms certain clotting factors, so the test that reflects how anticoagulated the blood is should measure the overall clotting tendency affected by these factors. Prothrombin time was the traditional measure, but PT values vary a lot depending on the lab’s reagent. The INR standardizes this result so you can reliably compare values across different labs and adjust warfarin dosing to stay within a safe therapeutic range. That standardized metric is what clinicians rely on to gauge anticoagulation in patients taking warfarin.

Note that aPTT is used to monitor heparin therapy, not warfarin, so it doesn’t indicate warfarin-related anticoagulation. Glucose and potassium are not used to monitor anticoagulation.