Relation of onset of platelet count decrease and onset of HIT-associated thrombosis.

The data summarize 209 patients with HIT-associated thrombosis. About one quarter (26.3%) of patients develop thrombosis on the same day that the thrombocytopenia occurs (defined arbitrarily as the day the platelet count has fallen by more than 50%), and in 33.5% the platelet count reached thrombocytopenia levels only after the occurrence of thrombosis.

Reprinted, with modifications, with permission.¹²