Canadian Practical Nurse Registration Examination (CPNRE) 2026 – 400 Free Practice Questions to Pass the Exam

Monitoring PT (Prothrombin Time) and INR (International Normalized Ratio) is critical before administering Warfarin because these tests assess the effectiveness of Warfarin in anticoagulation therapy. Warfarin is an anticoagulant that works by inhibiting vitamin K-dependent clotting factors, which prolongs the clotting time.

The INR, specifically, is a standardized measure used to evaluate the anticoagulant effect in patients on Warfarin, allowing for consistent and accurate dosing adjustments to prevent complications such as thrombosis or bleeding. PT gives insight into the extrinsic and common pathways of coagulation, which is directly affected by Warfarin therapy.

In contrast, the other tests listed do not directly relate to Warfarin's mechanism of action or its monitoring requirements. PTT (Partial Thromboplastin Time) and aPTT (Activated Partial Thromboplastin Time) are more relevant for heparin monitoring rather than Warfarin. The lipid panel and electrolyte panel do not provide essential information regarding bleeding risk or anticoagulation status. Thus, focusing on PT and INR is vital to ensure safe and effective Warfarin management.