Laboratory Diagnostics for Thrombosis and Hemostasis Testing—Part IV

This is the fourth themed issue of Seminars in Thrombosis and Hemostasis (STH) focused on laboratory diagnostics. We are pleased to include two in-depth reviews covering the performance of D-dimer assays in clinical laboratories, as summarized by two external quality assessment (EQA) programs serving different parts of the world.[1] [2] D-dimer testing is non-standardized and non-harmonized but has important clinical uses for the exclusion of venous thromboembolism, diagnosis of disseminated intravascular coagulation, and provides prognostic information in serious illnesses, such as coronavirus disease 2019. Thus, the real-world performance of these assays has significant clinical implications.