自从Emmett和Narins将血浆阴离子隙(AGb)的概念引进临床后,临床已普遍应用AGb来诊断和鉴别代谢性酸中毒(代酸)。而尿阴离子隙(AGu)引入临床已达5年之久,由于有关文献报道较少,尚无综述,对其实用意义缺乏了解,因而至今临床上仍很少采用。为了提高临床医师对这项检验的认识,本文将AGu的概念及用途概述如下。AGu为24小时尿Na~++K~+-Cl~-,通常简写为AGu=Na~++K~+-Cl~-。其来源与AGb一样,基于尿中电解质电中性原理,即尿Na~++K~++Ca~(2+)+ Since the introduction of the concept of plasma anion gap (AGb) by Emmett and Narins in clinical practice, AGb has been used clinically to diagnose and identify metabolic acidosis (acidosis). Urinary anion gap (AGu) has been introduced into clinical practice for 5 years. However, there is still no review on its practical significance due to the small number of reports in the literature. Therefore, it has been rarely used clinically so far. In order to enhance the clinician’s understanding of this test, this article summarizes the concept and use of AGu as follows. AGu is 24 hours urinary Na ~ ++ K ~ + -Cl ~ -, usually abbreviated as AGu = Na ~ ++ K ~ + -Cl ~ -. Its origin is the same as that of AGb. Based on the neutral principle of electrolytes in urine, the urinary Na ~ ++ K ~ ++ Ca ~ (2 +) +