Which statement correctly identifies the therapeutic range for warfarin anticoagulation as reflected by INR?

Which statement correctly identifies the therapeutic range for warfarin anticoagulation as reflected by INR?

• A. INR around 2.8
• B. INR around 1.0
• C. INR around 4.5
• D. INR around 1.5

Answer: (A)

Warfarin is monitored with the International Normalized Ratio (INR) to keep blood thinning within a safe range—enough to prevent clots but not so much that bleeding occurs. For most indications, the therapeutic goal is an INR of about 2.0 to 3.0, with some situations (like certain mechanical heart valves) requiring a slightly higher target up to around 3.5. An INR of 2.8 sits squarely within this common therapeutic window, indicating effective anticoagulation without being overly high. An INR near 1.0 would mean normal clotting tendency, not enough anticoagulation. An INR around 4.5 would be above the therapeutic range and carries a higher risk of bleeding, requiring intervention. An INR around 1.5 is subtherapeutic and may not adequately prevent clot formation.

Warfarin is monitored with the International Normalized Ratio (INR) to keep blood thinning within a safe range—enough to prevent clots but not so much that bleeding occurs. For most indications, the therapeutic goal is an INR of about 2.0 to 3.0, with some situations (like certain mechanical heart valves) requiring a slightly higher target up to around 3.5. An INR of 2.8 sits squarely within this common therapeutic window, indicating effective anticoagulation without being overly high.

An INR near 1.0 would mean normal clotting tendency, not enough anticoagulation. An INR around 4.5 would be above the therapeutic range and carries a higher risk of bleeding, requiring intervention. An INR around 1.5 is subtherapeutic and may not adequately prevent clot formation.