eTable 3. ADAMTS13 activity <10%: thrombotic thrombocytopenic purpura.

aTTP	Suspected cTTP/ Upshaw–Schulman syndrome
Anti-ADAMTS13 inhibitor positive	Anti-ADAMTS13 inhibitor negative, mutation analysis
Continue plasmapheresis, steroids, rituximab (off-label use)	Plasma infusion if acute organ damage, plasmapheresis

ADAMTS13: a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13; aTTP: immune-mediated, acquired thrombotic thrombocytopenic purpura; cTTP: congenital thrombotic thrombocytopenic purpura; TTP: thrombotic thrombocytopenic purpura