Question

. What are the problems that can occur with the quality of blood film?

Answer 1

Following problems may occur with quality of blood films:

1. During blood film preparation as soon as the drop of blood is placed on the glass slide, the smear should be made without delay. Any delay results in an abnormal distribution of the white blood cells, with many of the large white cells accumulating at the thin edge of the smear.

2. Blood films that are too thin or too thick present a problem. Extremely thin films (caused by too small a drop, too slow spreading or too low a spreader angle), may result in RBCs that appear as spherocytes and increased WBCs, such as monocytes and neutrophils, in the tails. An incorrect differential will result. Always scan the film under low power to detect this aberration.

3. Blood films with excessive tails or gritty feathered ends indicate a spreader edge that is rough or dirty, or an accumulation of leukocytes due to either slow spreading or a very high leukocyte count.

4. A properly air dried smear should be fixed within 4 hours of preparation but preferably within one hour. Good fixation requires about 10 to 20 minutes. Improper fixation causes artefactual burr cells (crenated red cells with refractile borders). Drying or fixation problems can result in variably shaped refractile inclusions in the erythrocytes; these may be confused with erythrocyte parasites.