[A patient with EDTA-dependent pseudothrombocytopenia who underwent emergent clipping surgery for a ruptured aneurysm].

A 42-year-old female with EDTA-dependent pseudothrombocytopenia underwent emergent clipping surgery for a ruptured aneurysm. On admission, the platelet count was low, but bleeding time and coagulation test were within normal limits. The blood smear anticoagulated with EDTA revealed remarkable agglutination of platelets, while heparinized blood showed a normal level. Diagnosis of EDTA-dependent pseudothrombocytopenia was made. The progressive drop in platelet count occurred within 10 minutes in the presence of EDTA. The autocounter misjudged the agglutination of platelets as red or white blood cells. The earlier study reported the incidence of this diseases as 0.07%. This disease is often misdiagnosed. Therefore, thrombocytopenia without any clinical symptom should be considered as showing a possible symptom of EDTA-dependent pseudothrombocytopenia.