A patient's platelet count drops 4 days after being placed on heparin. Select the correct interpretation

a. The patient has heparin-induced thrombocytopenia.
b. The patient has benign, limited thrombocytopenia related to heparin.
c. A bleeding time should be performed to evaluate qualitative platelet disorders.
d. An immunoassay for heparin-dependent anti-platelet factor 4 (PF4) should be performed to distinguish heparin-induced thrombocytopenia from benign, limited thrombocytopenia related to heparin.

ANS: D
This pattern, a drop in the platelet count 4 days after being placed on heparin, suggests heparin-induced thrombocytopenia. It could also be a benign, limited thrombocytopenia related to heparin. Assays such as the immunoassay for heparin-dependent anti-PF4 can distinguish the two.