Anticoagulant-induced pseudothrombocytopenia in a patient presenting for coronary artery bypass grafting

A 73-yr-old man with severe ischaemic heart disease presented for coronary artery bypass grafting. His preoperative platelet count, obtained from an e thylene diamine tetraacetic acid (EDTA) sampling bottle, was 61x10(9) litre (-1), but he had no history of bleeding problems. Previous platelet counts demonstrated results ranging from 16x10(9) litre(-1) to 254 x 10(9) litre(- 1) with variable degrees of in vitro platelet clumping. Preoperative thromb elastography reflected a normal coagulation profile. The laboratory finding s and the absence of a history of haemorrhagic complications suggested a di agnosis of EDTA-dependent pseudothrombocytopenia. We present the perioperat ive implications of this in vitro phenomenon and methods of detecting the f unctional and numerical integrity of circulating platelets.