失落感是存在於人類生活中的一種普遍現象，是種對個體重要的人或事物被剝奪的情感經驗。失落感常讓護理之家老年住民有被遺棄的感覺、缺乏安全感、孤寂、無望感等，進而影響對生命意義的看法，情緒低落無法調適者，更會有自殺的意念產生。然而，過去文獻並未對失落感的概念做有系統的概念分析，因此，本文旨在運用Walker和Avant（2005）的概念分析步驟，來澄清失落感的定義性特徵，確認失落概念的箝制因子及可能引起的後果。從典範案例中了解失落的定義性特徵，從邊緣相反案例中了解失落概念與其他相關概念的不同。期使透過此概念分析的結果，能增進護理人員對失落概念有進一步的了解，並應用於護理之家老年住民的照護。

Loss is a phenomenon common to the human experience. Feelings of loss represent an emotional response to separation from subjectively important person(s) or things. Loss often leaves nursing home elderly residents feeling abandoned, insecure, lonely, and hopeless and may affect their perception of the meaning of life. Those who are unable to adjust may slip into a depressed mood, which may lead to suicidal ideations. No systematic analysis of loss has been conducted. The purpose of this paper is to expand understanding of the concept of loss. The authors intend to clarify the defining attributes of loss, identify the antecedents that influence the perception of loss and discuss the possible consequences of loss using Walker and Avant’s (2005) concept analysis. A model case is used to demonstrate how loss is tied to these critical attributes. Borderline and contradictory cases are presented to differentiate between the concept of loss and other concepts. It is believed that this analysis will help nursing staff to gain a better understanding of the concept of loss and help them apply this knowledge in clinical practice.