ADAMTS13 and thrombotic thrombocytopenic purpura: Thrombocytopenia is not common in COVID-19 and was not directly associated with low ADAMTS13 activity levels in our cohort.31Also, lack of severe ADAMTS13 activity deficiency (only two patients had ADAMTS13 activity <10%) and lack of anti-ADAMTS13 antibodies in our patients excludes thrombotic thrombocytopenic purpura (TTP)32and may be more suggestive of secondary TMA, sepsis, or DIC.