Which of the following statement(s) is/are true concerning heparin-associated thrombocytopenia?

b. Severe thrombocytopenia (platelet count less than 100,000) is seen in less than 10% of patients treated with heparin

c. Heparin-associated thrombocytopenia is due to the aggregation of platelets and may result in thrombosis or embolic episodes

Heparin-associated thrombocytopenia occurs in 0.6% to 30% of patients who receive heparin, although severe thrombocytopenia (platelet counts less than 100,000) is seen in fewer than 10% of patients treated with heparin. It is caused by a plasma factor, most likely a heparin-dependent platelet antibody, that causes aggregation of platelets when exposed to heparin. Activation of platelets in this setting results in thrombocytopenia, thrombosis and embolic episodes, which can lead to death. Both bovine and porcine heparin have been associated with this syndrome, which usually begins 5 to 15 days after initiating heparin therapy. Even trivial exposure with heparin such as coating on pulmonary artery catheters or low rate infusion into arterial catheters may cause this syndrome.