NHA Certified Clinical Medical Assistant (CCMA)Clinical Patient CareMedium
A medical assistant is reviewing a patient's medication list and notes that the patient is taking Warfarin. Which of the following laboratory tests is most critical to monitor for this patient?
- AProthrombin Time (PT/INR)
- BBasic Metabolic Panel (BMP)
- CComplete Blood Count (CBC)
- DThyroid Stimulating Hormone (TSH)
Show answer & explanationAnswer & explanation
Correct answer: A. Prothrombin Time (PT/INR)
Warfarin is an anticoagulant that works by interfering with vitamin K-dependent clotting factors. The Prothrombin Time (PT) and its standardized ratio, the International Normalized Ratio (INR), are specifically used to monitor the effectiveness of Warfarin therapy and adjust dosage to prevent both excessive bleeding and clotting.
Why the other options are wrong
- B. A BMP assesses electrolytes, kidney function, and blood glucose, which is not directly related to Warfarin monitoring.
- C. A CBC measures various blood components and is useful for general health but not specific for monitoring Warfarin's anticoagulant effect.
- D. TSH is a thyroid function test and has no direct relevance to monitoring Warfarin therapy.
Warfarin Monitoring
Regular laboratory testing required to ensure that Warfarin, an anticoagulant, is at a therapeutic level without causing excessive bleeding or clotting.
- Warfarin inhibits vitamin K-dependent clotting factors.
- Monitored by Prothrombin Time (PT) and International Normalized Ratio (INR).
- Therapeutic INR range typically 2.0-3.0 for most conditions.
- Dosage adjusted based on INR results.
Memory trick: Warfarin Wants INR Watch