Heparin-induced thrombocytopenia in critically ill patients.

Critically ill patients commonly evince thrombocytopenia, either evident on admission to the intensive care unit (ICU) or that develops during their stay. Heparin-induced thrombocytopenia (HIT) explains thrombocytopenia in only approximately 1/100 critically ill patients; also, only 1 or 2 in 10 ICU patients with a positive PF4-dependent enzyme immunoassay has “true” HIT. Thus, there is major potential for overdiagnosis of HIT in the ICU. A recent study showing that dalteparin is associated with a reduced frequency of HIT indicates that critically ill patients too can benefit from the HIT-reducing potential of this low molecular weight heparin preparation.