A spreader slide that has damaged or unpolished ends.
(d) The use of dirty, dusty, greasy, or scratched slides.
(4) If slides cannot be stained immediately, they should be dried and then
fixed in methyl alcohol for 30 minutes.
(5) In cases of marked leukopenia, smears can be prepared from the white
cell layer ("huffy coat") obtained by centrifuging the blood slowly in a Wintrobe
hematocrit tube at 500-800 rpm for 5 minutes.
(6) It is important that the blood film be completely dried before staining;
otherwise the wet areas will wash off the slide.
(7) Protect blood slides from insects such as flies, cockroaches, etc. They
can "clean" raw blood slides very rapidly.
(8) Protect slides from areas of high humidity. Excessive moisture tends to
hemolyze red blood cells.
(9) Slides should be stained as soon as possible after preparation. White
cells tend to become distorted and disintegrate very rapidly, thus causing considerable
difficulty in identification.
(10) Very little actual staining takes place during the fixation stage. Most of
the staining actually occurs during the buffering stage.
(11) During the buffering stage, it is important that only amounts of buffer
equal to the stain be added, otherwise there is a tendency to over-dilute, causing the
smear to stain weakly.
(12) After the staining is complete, do not blot the smear but air-dry it. To
speed up the drying process, the smear can be placed in the heat of the substage light.
It is important that the slide not be heated too intensely or too long since overheating
tends to darken the staining reaction.
(13) A good quality smear should macroscopically pinkish-gray in hue. It
should not be blue, green, or red. Microscopically, the red blood cells should be pink to
orange and the white blood cells bluish if they display their true staining color.
(14) If the RBCs are bluish or green, this indicates that the stain is too
alkaline. With an alkaline stain, the WBCs stain heavily and generally display fair
distinguishing characteristics. However, the heavy stain masks any abnormalities of the
RBCs. Heavy staining can be caused by:
(a) Blood smears which are too thick.