Pseudothrombocytosis and pseudoleukocytosis in a case of essential mixed cryoglobulinemia (type II).

Pseudothrombocytosis and pseudoleukocytosis occurred in a patient with essential mixed cryoglobulinemia (EMC) and atypical cutaneous ulcers, when the blood cell counts were estimated by the Model S Plus Coulter Counter. The spurious cell counts were found in serum as well as in plasma and whole blood, so the involvement of fibrinogen in this phenomenon is questioned. When timed serial counts were performed on whole blood at room temperature the highest value of WBCs was detected one hour after sample collection and that of platelets occurred at 6 hours, when leukocytosis had disappeared. Possible explanations for this phenomenon are offered.