INR on warfarin is typically within which range?

INR on warfarin is typically within which range?

• A. 1-2 seconds
• B. 0-1 second
• C. 2-3 seconds
• D. 3-4 seconds

Answer: (C)

Warfarin therapy is guided by the INR, a standardized measure of how long blood takes to clot. For most people on warfarin, the therapeutic goal is an INR about 2.0 to 3.0. This level gives enough anticoagulation to prevent clots while minimizing bleeding risk. Normal INR is around 0.8–1.2, so values significantly above 1.2 indicate some anticoagulation, with 2.0–3.0 being the typical target. Values below 2.0 may not prevent clots, while values above 3.0 increase bleeding risk. The listed range of 2–3 seconds roughly corresponds to the commonly targeted therapeutic zone, whereas the other options imply too little or too much anticoagulation. In some valve situations, a slightly higher range may be used, but 2–3 is the standard teaching range.

Warfarin therapy is guided by the INR, a standardized measure of how long blood takes to clot. For most people on warfarin, the therapeutic goal is an INR about 2.0 to 3.0. This level gives enough anticoagulation to prevent clots while minimizing bleeding risk. Normal INR is around 0.8–1.2, so values significantly above 1.2 indicate some anticoagulation, with 2.0–3.0 being the typical target. Values below 2.0 may not prevent clots, while values above 3.0 increase bleeding risk. The listed range of 2–3 seconds roughly corresponds to the commonly targeted therapeutic zone, whereas the other options imply too little or too much anticoagulation. In some valve situations, a slightly higher range may be used, but 2–3 is the standard teaching range.