Here’s a good question about two entities that sound the same (but aren’t).
Q. What is the difference between heparin associated thrombocytopenia (HAT) and heparin induced thrombocytopenia (HIT)?
A. Heparin-induced thrombocytopenia (HIT) is defined as a decrease in platelet count during or shortly after heparin exposure. There are two types of HIT:
1. HIT type I (used to be called heparin-associated thrombocytopenia) – a benign, probably non-immune form of HIT that is not associated with an increased risk of thrombosis. It is mild, with platelet counts rarely dipping below 100,000. It affects up to 10% of patients receiving heparin treatment, and it disappears with withdrawal of heparin.
2. HIT type II – an immune-mediated type of HIT that is associated with an increased risk of thrombosis. It is associated with significant morbidity and mortality if unrecognized.