Kraut Jeffrey A, Madias Nicolaos E
Medical and Research Services VHAGLA Healthcare System, UCLA Membrane Biology Laboratory, and Division of Nephrology VHAGLA Healthcare System and David Geffen School of Medicine, Los Angeles, California 90073, USA.
Clin J Am Soc Nephrol. 2007 Jan;2(1):162-74. doi: 10.2215/CJN.03020906. Epub 2006 Dec 6.
The serum anion gap, calculated from the electrolytes measured in the chemical laboratory, is defined as the sum of serum chloride and bicarbonate concentrations subtracted from the serum sodium concentration. This entity is used in the detection and analysis of acid-base disorders, assessment of quality control in the chemical laboratory, and detection of such disorders as multiple myeloma, bromide intoxication, and lithium intoxication. The normal value can vary widely, reflecting both differences in the methods that are used to measure its constituents and substantial interindividual variability. Low values most commonly indicate laboratory error or hypoalbuminemia but can denote the presence of a paraproteinemia or intoxication with lithium, bromide, or iodide. Elevated values most commonly indicate metabolic acidosis but can reflect laboratory error, metabolic alkalosis, hyperphosphatemia, or paraproteinemia. Metabolic acidosis can be divided into high anion and normal anion gap varieties, which can be present alone or concurrently. A presumed 1:1 stoichiometry between change in the serum anion gap (DeltaAG) and change in the serum bicarbonate concentration (DeltaHCO(3)(-)) has been used to uncover the concurrence of mixed metabolic acid-base disorders in patients with high anion gap acidosis. However, recent studies indicate variability in the DeltaAG/DeltaHCO(3)(-) in this disorder. This observation undercuts the ability to use this ratio alone to detect complex acid-base disorders, thus emphasizing the need to consider additional information to obtain the appropriate diagnosis. Despite these caveats, calculation of the serum anion gap remains an inexpensive and effective tool that aids detection of various acid-base disorders, hematologic malignancies, and intoxications.
血清阴离子间隙由化学实验室测定的电解质计算得出，定义为血清钠浓度减去血清氯和碳酸氢盐浓度之和。该指标用于酸碱平衡紊乱的检测与分析、化学实验室质量控制评估以及多发性骨髓瘤、溴中毒和锂中毒等疾病的检测。其正常值范围差异较大，这既反映了测量其组成成分方法的不同，也体现了个体间的显著差异。低值最常见于实验室误差或低白蛋白血症，但也可能提示存在副蛋白血症或锂、溴或碘中毒。高值最常见于代谢性酸中毒，但也可能反映实验室误差、代谢性碱中毒、高磷血症或副蛋白血症。代谢性酸中毒可分为高阴离子间隙型和正常阴离子间隙型，两者可单独或同时存在。血清阴离子间隙变化（ΔAG）与血清碳酸氢盐浓度变化（ΔHCO₃⁻）之间假定为1:1的化学计量关系，已被用于揭示高阴离子间隙酸中毒患者混合性代谢酸碱平衡紊乱的并存情况。然而，近期研究表明该疾病中ΔAG/ΔHCO₃⁻存在变异性。这一观察结果削弱了仅使用该比值检测复杂酸碱平衡紊乱的能力，因此强调需要考虑其他信息以做出准确诊断。尽管存在这些注意事项，但血清阴离子间隙的计算仍然是一种廉价且有效的工具，有助于检测各种酸碱平衡紊乱、血液系统恶性肿瘤和中毒情况。
