NCLEX-PN® ExaminationReduction of Risk PotentialMedium
An LPN is caring for a client with a new prescription for warfarin. The LPN should recognize that which laboratory value is used to monitor the therapeutic effects of warfarin?
- AProthrombin time (PT) and International Normalized Ratio (INR)
- BActivated partial thromboplastin time (aPTT)
- CPlatelet count
- DFibrinogen level
Show answer & explanationAnswer & explanation
Correct answer: A. Prothrombin time (PT) and International Normalized Ratio (INR)
Warfarin is an anticoagulant that inhibits vitamin K-dependent clotting factors. Its therapeutic effect is monitored by measuring the prothrombin time (PT) and its standardized value, the International Normalized Ratio (INR).
Why the other options are wrong
- B. aPTT is used to monitor heparin therapy.
- C. Platelet count assesses platelet function and number, not directly warfarin's effect.
- D. Fibrinogen level is a general coagulation factor, not specific for warfarin monitoring.
Warfarin Monitoring
Regular laboratory testing to ensure warfarin's anticoagulant effect is within a therapeutic range, preventing both excessive bleeding and clot formation.
- Warfarin is a vitamin K antagonist.
- Monitored by PT/INR.
- Therapeutic INR range is typically 2.0-3.0 for most conditions.
Memory trick: Warfarin is 'War P-T/INR', Heparin is 'Hep aPTT'.