Ethylenediaminetetraacetic Acid-induced Pseudothrombocytopenia in Association with Graves' Hyperthyroidism.

Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia (EDTA-PTCP) is an in vitro phenomenon of EDTA-induced platelet aggregation. A number of mechanisms have been proposed to account for this phenomenon. EDTA-PTCP has been found in healthy subjects and patients with a variety of conditions, including viral infections, cardiovascular disease, liver disease, neoplastic diseases and autoimmune diseases. In the present case, a 66-year male had a 5-month history of palpitations. The patient presented with Graves' hyperthyroidism and was diagnosed with transient EDTA-PTCP. With the improvement of hyperthyroidism, the phenomenon of EDTA-PTCP disappeared. So far, EDTA-PTCP related to Graves' hyperthyroidism has not been reported in the literature. Key Words: Hyperthyroidism, Thrombocytopenia, Autoimmune diseases, Platelet aggregation, Edetic acid.