Validation of D‐Dimer as a Prognostic Biomarker in Transplant‐Associated Thrombotic Microangiopathy in Children

Severe transplant-associated thrombotic microangiopathy (TA-TMA), defined as multi-organ dysfunction (MOD), is a life-threatening complication of hematopoietic cell transplantation (HCT). We previously showed that D-dimer is a novel prognostic marker; levels ≥574 mg/L at TA-TMA diagnosis predicted the development of MOD. In this independent cohort of children with TA-TMA (n = 45), D-dimer levels ≥574 mg/L at diagnosis predicted MOD, with a sensitivity of 94.4 (95% confidence interval [CI]: 72.7-99.9) and a specificity of 63.6 (95% CI: 30.8-89.1). Ready availability and low cost make D-dimer a promising marker for predicting patients at risk for developing severe disease and may inform treatment approaches.