Difficulties of Automatic platelet count

Abstract

Platelet count constitutes a capital test of which results have an effect on the clinical or therapeutical decisions. The last generation of automated hematology analyzers associate impedance measure techniques and optical methods (laser diffraction and fluorescence) to obtain a figure nearest to reality. However, counting errors per excess (pseudothrombocytosis) or default (pseudothrombocytopenia) exist and do not have to be ignored. The multiple causes responsible for these errors are listed but the list is not exhaustive. Aggregation of platelets EDTA-dependent is the most common cause of pseudothrombocytopenia. However difficulties to discriminate platelets from other particles with similar size, density or diffraction as small erythrocytes, cytoplasmic fragments of some leukocytes, fibrin filaments, lipids or bacteria, may cause pseudothrombocytosis. A simple decisional diagram is proposed to solve the downward biases of the rate of the platelets or pseudothrombocytopenia. It can be useful in the daily management of the isolated and random thrombocytopenia cases.