一位服用華法林（Warfarin）的病人，下列哪項評估結果需要立即處置？

Warfarin 會抑制凝血因子，導致凝血功能下降。黑便（tarry stools）代表上消化道出血，是嚴重的抗凝血劑副作用。INR 2.5 在治療範圍內；瘀青在抗凝劑治療中常見，但非最危急；攝取綠色蔬菜會影響藥效但非立即危急狀況。

Warfarin inhibits clotting factors, reducing coagulation function. Black, tarry stools indicate upper gastrointestinal bleeding, a serious adverse effect of anticoagulant therapy. An INR of 2.5 is within therapeutic range; bruising is common with anticoagulants but is not the most urgent finding; and intake of green leafy vegetables affects drug efficacy but is not an immediate emergency.

美台臨床對於抗凝血劑衛教一致，皆強調監測出血徵兆。台灣病人常擔心食物交互作用而完全不吃蔬菜，需教育其應保持穩定攝取。