病人正在服用 Warfarin。護理師應監測哪項檢驗值以評估藥效？
A patient is prescribed warfarin therapy. Which laboratory value should the nurse monitor to evaluate the effectiveness of this medication?
- AHemoglobin level血紅素濃度
- BPT/INR✓ 正解凝血酶原時間/國際標準化比值
- CPlatelet count血小板計數
- DaPTT活化部分凝血活酶時間
Warfarin 是一種維生素 K 拮抗劑，透過抑制肝臟中依賴維生素 K 的凝血因子（II, VII, IX, X）合成來發揮抗凝血作用。為了評估其治療效果，臨床上使用凝血酶原時間（PT）並將其標準化為國際標準比值（INR）。INR 能消除不同實驗室試劑敏感度差異，是監測 Warfarin 的標準指標。其他選項如 aPTT 用於監測 Heparin，血小板與血紅素則與抗凝血療效監測無直接關聯。
Warfarin acts as a vitamin K antagonist by inhibiting the synthesis of vitamin K-dependent clotting factors. Prothrombin time (PT) and its standardized International Normalized Ratio (INR) are the gold standard for monitoring therapeutic efficacy because INR accounts for variations in laboratory reagents. While aPTT monitors heparin therapy, platelet counts and hemoglobin levels do not directly assess anticoagulation status.