Abstract: Antithrombin (AT) activity testing is widely used for the diagnosis of hereditary or acquired AT deficiency and for therapeutic monitoring in various diseases. However, laboratories in China face various challenges in testing procedures, quality control, and appropriateness evaluation. This consensus integrates relevant Chinese and international literature on AT activity testing and current practices in China to summarize key issues and propose consensus recommendations, with the aim of standardizing AT activity testing, improving laboratory testing quality, and laying the foundation for establishing standards for related individualized therapies.