The International Standard for Diphtheria Antitoxin Equine is essential for the standardisation of assays used to determine the potency of therapeutic diphtheria antitoxin products produced from equine serum. This paper describes the production and characterization of the 2nd International Standard for Diphtheria Antitoxin Equine and its calibration in International Units. Calibration was performed by toxin neutralization test in vivo and in vitro (Vero cell assay), and potency was expressed relative to the 1st International Standard to ensure continuity of the International Unit. The candidate standard (NIBSC product code 18/180) was assigned a unitage of 57 IU/ampoule based on results from 14 laboratories in 9 different countries and was established by the World Health Organisation Expert Committee on Biological Standardization in 2021.

马白喉抗毒素国际标准对于用于确定由马血清生产的治疗性白喉抗毒素产品效力的测定的标准化至关重要。本文介绍了第二版马白喉抗毒素国际标准品的生产和表征及其国际单位校准。通过体内和体外毒素中和试验进行校准（Vero 细胞测定），并相对于第一个国际标准表示效力，以确保国际单位的连续性。候选标准品（NIBSC 产品代码 18/180）根据来自 9 个不同国家的 14 个实验室的结果分配了 57 IU/ampoule 的单位，由世界卫生组织生物标准化专家委员会于 2021 年制定。