Comparison of the classical manual pushed wedge films, with an improved automated method for making blood smears.

Comparison of apparatus for automatically spreading peripheral blood films (GENES) to manual wedge-pull technique has been performed, showing that the average size of optimal area for counting is twice larger in automated smears compared to manual ones. The variability of WBC repartition has been studied in doing differential count on manual and automated smears and both are compared to results obtain with an independent technique (Coulter STKS) for differential. The correlation coefficients for each WBC population show a closer relationship between automated smear preparations and reference instrument (STKS) than with manual spreading smears. Monocyte differential is particularly influenced by the variability of manual spreading procedures.