Manual of basic techniques for a health laboratory - libdoc.who.int

302 Manual of basic techniques for a health laboratoryFig. 9.67 Draw the spreader back until it touches the drop of bloodFig. 9.68 Allow the blood to run along the edge of the spreaderFig. 9.69 Push the spreader to the end of the slide witha smooth movementFig. 9.70 Correctly (a) and incorrectlyprepared (b) blood films6. Check that the film is satisfactory as shown in Fig. 9.70 (a).● There should be no lines extending across or down through the film.● The film must be smooth at the end, not ragged and lined as shown inFig. 9.70 (b).● The film must not be too long.● The film must not be too thick.● The film must not contain holes because a greasy slide has been used.A well-spread film is of great importance. A badly spread film will give the wrongleukocyte type number fractions and make it impossible to report erythrocytemorphology.