The film is made from a drop of blood spread evenly on a slide and stained. It is important to ensure that the film is well-made and well-stained.
Preliminary preparation
a) Specimen
Ideally, film should be prepared directly from a skin puncture or within one hour of blood collection into EDTA. (Why?)
b) Spreader
The spreader is made from a glass slide that has a smooth end. Using a glass cutter, break off one corner of the slide, leaving a width of about 18 mm as a spreader. A spreader can be used repeatedly unless the edge becomes chipped, but it must be thoroughly washed.
c) Clean slides
It is essential to use clean, dry and dust-free slides measuring 75 x 25 mm and approximately 1 mm thick.
Preparation of blood smear
a) Adequate mixing of the specimen.
b) Place a small drop of blood in the centre line of a slide, 1 cm from one end.
c) Then, without delay, place a spreader in front of the drop at an angle of about 30 degrees and move it back to make contact with the drop.
d) The drop should spread out quickly along the line of contact.
e) With a steady movement of the hand, spread the drop of blood along the slide.
1) The spreader should not be lifted until the last trace of blood has been spread out.
g) The film should be about 3 cm in length and finish at least 1 cm before the end of the slide.
h) The film should be allowed to dry in the air.