[Assessment of an immature platelet fraction (IFP%) in the diagnosis of thrombocytopenia].

Reticulated platelets are young platelets containing mRNA. They reflect the rate of thrombopoesis. The aim of this study was to evaluate the reliability of the percentage of reticulated platelets (IPF%) as a diagnostic test for thrombocytopenia pathogenesis. IPF% was measured using XE 2100 Sysmex. An IPF% reference range in 52 healthy individuals was established as 1-4.5% with a median 2.2%. In all the 13 patients with idiopathic thrombocytopenic purpura IPF% was increased (median 11.8, range 5.3-54.3%). Only 7 out of 18 patients with disseminated intravascular coagulation had high IPF% (median 5.4%, range 2.9-14.1%). Surprisingly, IPF% was increased in 17 out of 22 patients with acute leukaemia (median 9.7%, range 0.9-41.9%). In CIVD, IPF% values correlated with the severity of the illness. Increased values in acute leukaemia could not be explained by non specific staining but by delayed maturation of reticulated platelets. A high IPF% does not substantiate hyperdestructive thrombocytopenia but a diagnosis of idiopathic thrombocytopenic purpura should be questioned if IPF% is not raised.