John Libbey Eurotext

Hématologie

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Schistocytes measurement in the laboratory of haematology Volume 13, issue 3, Mai-Juin 2007

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Authors
Service d’hématologie biologique, CHU Nancy, 54511 Vandoeuvre, Unité de transplantation médullaire, CHU Nancy, Laboratoire d’hématologie, CHU Caen

The schistocytes are fragmented red blood cells mainly observed in the setting of haemolytic anaemias and particularly among the thrombotic microangiopathies. The presence of schistocytes is an important criterion for the diagnosis mechanical anaemias, though the identification of these cells remains problematic. As we observed a high variability of the morphologic identification criterias of the schistocytes among morphologists, we proposed some guidelines in a text of recommendations (Delphi method, participation of approximately 100 biologists, 2003). A schistocyte was defined as a red blood cell of decreased size, with a linear segment corresponding to the zone of fragmentation and the presence of angles (helmet, crescent, triangle shapes). The recognition of the schistocytes being observer-dependent, a computorised morphometric analysis of digitalized images should help, but does not exist yet! In a more practical way, we evaluated the contribution of the parameter fragmented red cell (FRC) available on some automated blood cells analyzers. A partial correlation between schistocytes observed on smear and automated counted FRC was found. The negative predictive value of the FRC was good to exclude the diagnosis of thrombotic microangiopathy. In conclusion, the morphologist should be aware of the difficulties of the research of the schistocytes on a blood smear and keep themselves up to date with the technological possibilities recently developed by the blood cells counters.