title: Causes for poor leukocyte distribution in manual spreader-slide blood films.
abstract: The need to evaluate newly available automation for producing peripheral blood films demanded a critical review of the techniques used to produce manual blood films. This study compared the effects of five variables on the distribution of leukocytes within manual (spreader-slide method) blood films: 1) shape of the feathered edge; 2) type of spreader used; 3) speed of stroke; 4) delay in spreading blood; and 5) cell concentrations within the sample. Duplicate blood films representing each technical variable were prepared from selected patient samples. Leukocyte counts per microscopic field and 200-cell differentials were determined within the body and within the edges of each film. The best relative leukocyte distribution for each specimen was consistently obtained with: 1) production of 'straight' feathered edges; 2) spreader slides having thin, planed, and polished edges; 3) 'fast' forward strokes; and 4) no delay in spreading the blood drop. Decreased erythrocyte numbers appeared to have a marked effect on leukocyte distribution.
mesh_terms: D001772:Blood Cell Count / Q000295:instrumentation / Q000379:methods*; D006400:Hematocrit; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes / Q000166:cytology