Thrombosis and hemostasis testing plays a pivotal role in the diagnosis, treatment, and monitoring of bleeding and thrombotic disorders. Due to the specialized characters and clinical demands, clinical laboratories carry out laboratory developed tests (LDT) to varying degrees. LDT must be validated to ensure that the performance meets clinical needs before they are introduced into routine use; however, clear operational specifications for this process have been lacking. In August 2025, the International Committee for Standardization in Haematology (ICSH) published the Guidance on the Validation of Laboratory Developed Tests in Haemostasis，which provided detailed definitions, performance verification requirements, and implementation strategies for LDT in this field. This article interprets the key provisions of the guideline, aiming to assist laboratory managers and technical personnel in understanding and applying these recommendations effectively.