INTRODUCTION
Blood samples sent to external laboratories are not always fresh enough to provide maximum information. A freshly prepared smear will enable the haematologist to make a more meaningful interpretation of red cell morphology in cases of anaemia. In addition, the identification of haemobartinella (a blood parasite) and Heinz bodies (erythrocyte refractile bodies, in large numbers indicative of degenerative processes as in depression anaemias) is more likely. Improved leukocyte preservation may help establish the presence of a left shift (increased numbers of immature neutrophils indicative of a toxic condition).

EQUIPMENT

• Lab coat.
• Paper towel.
• Grease free pre-cleaned slides.
• Spreader slides (proprietary plastic type or hand-made from cutting the corner off of a standard slide).
• Pencil for labelling slides.
• Slide rack.
• A well mixed EDTA blood sample.
• Plain capillary tubes.

METHOD

1. Put on your laboratory coat, and ensure that long hair is tied back and any jewellery removed.
2. Lay out some paper towel on a clean, dry, flat surface.
3. Lay out the slide/s and label them (in pencil - pen washes off if the slides are to be stained).
4. Use a plain capillary tube to draw up a small amount of blood from a well mixed EDTA sample.
5. Place a drop of blood (approximately the size of a pinhead) about half an inch away from the right hand end of the slide.
6. Place the spreader on the slide ahead of the drop of blood at a 45 degree angle.
7. Draw back the spreader to touch the drop of blood, and as the blood flows to the edge of the spreader, push the spreader firmly forward in one smooth movement (ensuring that you maintain the 45 degree angle).
8. The resultant smear should be thumb-shaped and smooth with no jagged edges and measure about half to one third of the length of the slide; repeat if more than 1 smear is required.
9. Air dry the smears.
10. Place the smears safely in a rack ready for staining.

NB. Please refer to the Key Notes section Blood Smears - Troubleshooting if you have any difficulty with this task.