Thursday, July 1, 2010

Thin Blood films

Value of blood films: Examination of thin blood films is important in the investigation and management of anaemia, infections, and other conditions which produce changes in the appearance of blood cells and differential white cell count. A blood film report can provide rapidly and at low cost, useful
information about a patient’s condition Thin blood film: Thin blood films can be made from free-flowing capillary blood or well mixed EDTA anticoagulated blood *Caution: Wear protective gloves when handling blood and follow safe working practices Technique of making a thin blood film: 1 Make a blood spreader from a slide which has ground glass polished sides 2 Place a drop of blood on the end of a clean dry slide as shown in video below. Avoid making the drop too large (if too large, use a drop from the excess blood to make the film) 3 Using a clean smooth edged spreader, draw the spreader back to touch the drop of blood and allow the blood to extend along the edge of the spreader. Holding the spreader at an angle of about (30)●, spread the drop of blood to make a film about 40–50 mm in length (two thirds of the slide) 4 Wipe clean the end of the spreader. 5 Immediately air dry the film by waving the slide back and forth. Protect the dried film from dust and insects. 6 When completely dry and within a few minutes of making the blood film, fix it in absolute methanol Features of a well made film ● Not too thick, nor too long ● Free from lines and holes ● Has a smooth ‘tail’ and for practical technique show the video below

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