Which laboratory value is critical to monitor for patients on warfarin?

Monitoring the International Normalized Ratio (INR) is essential for patients on warfarin because this anticoagulant works by inhibiting vitamin K-dependent clotting factors, which affects the coagulation pathway. The INR provides a standardized measure of how long it takes for blood to clot, allowing for consistent monitoring of the degree of anticoagulation across different laboratories and patient populations.

The INR helps clinicians assess whether a patient on warfarin is within the therapeutic range, which is crucial for preventing thromboembolic events while minimizing the risk of bleeding complications. Frequent INR monitoring allows for dose adjustments to ensure that patients remain within this safe and effective range.

While other laboratory values, such as a complete blood count, may be relevant in assessing overall health or detecting complications such as bleeding, they do not provide the specific information necessary to manage warfarin therapy effectively. Thus, maintaining an appropriate INR is critical for the safe and effective management of patients receiving warfarin therapy.