Documented sudden onset of pseudothrombocytopenia.

A 66-year-old male patient was hospitalized for severe heart failure. Within 3 days after admission his platelet count dropped from 148 x 10(9)/l to 3 x 10(9)/l. Pseudothrombocytopenia was diagnosed based on the platelet count of 3 x 10(9)/l in K3-EDTA anticoagulated blood as opposed to 110 x 10(9)/l in sodium citrate. Platelet reactive antibodies were not detectable. To the best of our knowledge, this is the first report of a documented onset of pseudothrombocytopenia.