護理師照護一位診斷為深層靜脈栓塞（DVT）並接受肝素（Heparin）滴注的病人。護理師應監測下列哪個實驗室數值以評估治療效果？
A nurse is caring for a client who is diagnosed with DVT and is receiving a heparin infusion. Which laboratory value should the nurse monitor to evaluate the effectiveness of this therapy?
- AInternational Normalized Ratio (INR)國際標準化比值 (INR)
- BPlatelet count血小板計數
- CActivated partial thromboplastin time (aPTT)✓ 正解活化部分凝血活酶時間 (aPTT)
- DProthrombin time (PT)凝血酶原時間 (PT)
肝素（Heparin）的作用機轉是加強抗凝血酶 III 的作用，影響內在凝血路徑，因此監測 aPTT 是評估肝素抗凝血效果的指標。PT/INR 用於監測華法林（Warfarin）療效。血小板計數雖重要（預防肝素誘發之血小板減少症，HIT），但非評估「抗凝血效果」的指標。正確劑量下 aPTT 通常維持在基準值的 1.5 到 2.5 倍。
Heparin works by enhancing the action of antithrombin III, affecting the intrinsic coagulation pathway; therefore, monitoring aPTT is the indicator for assessing heparin's anticoagulant effect. PT/INR is used to monitor warfarin therapy. Although platelet count is important (to prevent heparin-induced thrombocytopenia, HIT), it is not an indicator for evaluating 'anticoagulant effect.' With proper dosing, aPTT is generally maintained at 1.5 to 2.5 times the baseline value.
美台皆以 aPTT 監測 Heparin，且近年來許多醫院改用抗因子 Xa（anti-Xa）檢測，因其較不受其他因素干擾。