RADIL STANDARD OPERATING PROCEDURE FOR MAKING A BLOOD SMEAR
Peripheral blood or potassium EDTA anticoagulated blood (1-2 mg EDTA/1 ml blood) may be used. Smears of peripheral blood must be made immediately. Smears made from EDTA-anticoagulated blood should be made within 2 hours of collection. All specimens must be free of clots.
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Step 1. Place a 2-3mm drop of blood about 1cm from the frosted end of a clean slide that is on a flat surface. If using a needle and syringe, first remove the needle and then touch the end of the syringe to the slide. |
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If using a capillary tube, be sure to fill the capillary at least two-thirds with blood. Touch the end of the capillary to the slide. |
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Step 2. With the thumb and forefinger of the right hand, hold the end of a second slide (“spreader”) against the surface of the first slide at an angle of 30-45 degrees. |
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Step 3. Draw it back to contact the drop of blood. Allow the blood to spread and fill the angle between the two slides. |
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Step 4. Push the “spreader” slide at a moderate speed forward until all of the blood has been spread into a moderately thin film. |
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Alternatively, the slide may rest on the forefinger of the left hand. This may make it easier to maintain a moderate and consistent speed when “pushing” the “spreader” slide. |
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Note: The film should not cover the entire surface of the slide. In a good film, there is a thick portion and a thin portion and a gradual transition from one to the other. The film should have a smooth, even appearance and be free from ridges, waves, or holes. The end of the smear (the “feathered edge”) should be smooth and even. The edge of the “spreader” must be absolutely smooth. If it is rough, the film has ragged tails containing many leukocytes. |
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Shipping containers are available from most laboratory supply companies. It is important that the containers are sealed securely so that the slides won’t fall out during shipping. |