The haematological emergency - Thrombocytosis - Calendar 2008 month 11

In extreme microcytosis of the erythocytes, for example in severe iron deficiency anaemia, the microcytes may be falsely classified as platelets when assessed by impedance counting, simulating thrombocytosis. However, in such a case fluorescent staining and counting of platelets in the optical channel will always provide a correct result. The scattergram shows a real thrombocytosis (1,023,000/µL).

In the impedance channel of a haematology analyser a falsely elevated platelet concentration of 850,000/µL was measured. This was caused by precipitated cryoglobulin in cryoglobulinaemia. The flocculated cryoglobulin is visible in the phase contrast microscope in between the erythrocyte rouleaux.

Thromobocytosis of 1,300,000/µL and platelet anisocytosis in essential thrombocythaemia (ET).