NOTE: When performing the white cell
count, you may observe abnormal white
cells such as distorted lymphocytes,
smudge cells, and disintegrated cells.
Distorted lymphocytes, which appear
squashed or distorted, are caused by
excessive pressure on the cell during the
process of making the smear. Distorted
cells should be recorded as normal
Smudge cells are white
cells that have ruptured and only the
nucleus remains. Afew smudge cells may
be found in a normal blood smear.
Smudge cells should not be added to the
count or recorded.
are ruptured cells, but the nucleus and
cytoplasm still remain.
cells should not be counted as one of the
100 cells, but should be recorded on the
report as disintegrated cells.
8. Once the differential count is completed,
proceed to step 4, reporting the count.
NOTE: If it is desirable to save a smear
for reexamination, remove the immersion
oil by placing a piece of lens tissue over
the slide and moistening the tissue with
xylene. Draw the damp tissue across the
slide, and dry the smear with another
piece of lens paper.
REPORTING THE COUNT.When you have
calculated the differential count, the report is given
according to either the Schilling classification or
filament and nonfilament classification methods.
We will be covering the Schilling classification, since
it is the simplest and most popular method.
The Schilling Classification.The Schilling
classification was established when Victor Schilling, a
German hematologist, noticed that in many diseases
there is an increase in the percentage of immature
neutrophils. The blood chart he developed reported the
percentages of the different neutrophilic cell types and
(in part) was arranged in the following manner:
2 to 6
55 to 75
Note that the immature cells are on the left side of
the chart. If percentages of immature cell increased,
Schilling referred it as a shift to the left. When the
shift to the left was accompanied by a low white cell
count, Schilling called it a degenerative shift to the
left. A degenerative shift to the left is seen in such
diseases as typhoid fever. This shift is caused by a
depression of the cell factories in the bone marrow.
When the shift to the left is accompanied by a high
white cell count, it is called a regenerative shift to the
left. A regenerative shift to the left is seen in such
diseases as pneumonia. This shift is caused by a
stimulus of the cell factories in the bone marrow.
A shift to the right implies an increase in
It may be seen in
pernicious anemia, an anemia caused by the
malabsorption of vitamin B12.
The Schilling classification for an adult differen-
tial white cell count is provided below in table 7-2.
NOTE: Normal values for differential
counts vary with the age of the patient.
For example, childrens blood normally
contains 0% to 2% basophils, 0% to 5%
eosinophils, 25% to 75% neutrophils,
30% to 70% lymphocytes, and 0% to 8%
monocytes. Normal values may also be
adjusted by hospitals that have evaluated
the normal differential value for their
General Interpretations of Leukocyte
Changes.Together, the total white cell count and
differential count aid physicians in interpreting the
severity of infections. Some general interpretations of
leukocyte changes are as follows:
Leukocytosis with an increase in the percentage
of neutrophils indicates a severe infection with a
Neutrophilic band cells
2 to 6
Neutrophilic segmented cells
55 to 75
20 to 35
2 to 6
Eosinophilic segmented cells
1 to 3
Basophilic segmented cells
0 to 1
Table 7-2.Schilling Classification of the Differential White