EDTA-induced pseudothrombocytopenia.

: A 45-year-old man was admitted to the hospital because of unstable angina pectoris. During the wait for coronary artery bypass surgery, the platelet count gradually decreased from 154,000 to 20,000/mm3, without hemorrhagic manifestations. Medications were discontinued and surgery was postponed. Direct blood smear revealed a normal number of platelets, establishing the diagnosis of pseudothrombocytopenia. The mechanism of the development of pseudothrombocytopenia is not clear.