Normal Values. The normal percentages of the
different leukocytes are:
(Bases) 0-2 percent
(Monos) 4-8 percent
Metamyelocytes (Metas) 0 percent
Bands or Stab
(Bands) 0-10 percent
(Segs or 51-67percent
Most hospital corpsmen have heard the ex-
pression shift to the left and shift to the right.
These terms are often loosely used in referring to an
increase in bands or an increase in segs,
respectively. The true meaning of the terms can best
be explained by the following diagram:
The metamyelocytes, bands, and segmented
neutrophils constitute the neutrophilic cells. When
the cells to the left of the segs are increases, it is a
shift to the left. If the segmented neutrophils
increase, it is a shift to the right. The true right
shift will show numerous hypersegmented (having
six or more lobes) neutrophils.
General Interpretations of Leukocytic
The severity of an infection maybe determined
total white cell count and the differential by the
Leukocytosis (abnormally high white cell
count) with an increase in the percentage of
neutrophil indicates a severe infection with
a good response of the bone marrow. The
primary phagocytes (bacteria-destroying cells) are
the neutrophils, and the bone marrow should supply
large numbers of these to combat the infection. The
greater the shift to the left (increase in immature
neutrophils), the more severe the infection. The
(metamyelocytes) indicates irritation of the bone
marrow with regeneration. If the infection continues
and the patients resistance declines, the shift
advances further to the left. If improvement ensues,
the shift declines and recedes to normal.
A falling white cell count with the number
and maturity of neutrophils progressing
toward normal indicates recovery.
A continued shift to the left with a falling
total white cell count indicates a break-
down of the bodys defense mechanism and
is a poor prognosis.
The percentage of eosinophils, lymphocytes,
and monocytes generally decreases in acute
In tuberculosis an increase in monocytes
(monocytosis) indicates activity in the
infected area. An increase in lymphocytes
(lymphocytosis) indicates healing.
Eosinophils increase in parasitic infections
and allergic conditions.
Materials Required for Differential Count
Four plain glass microscope slides, clean
Wrights stain, powder or tablet form.
Prepare this stain as follows.
Tablets: Use one tablet for each 10
ml of reagent grade methyl alcohol.
Dissolve tablets after crushing
them with the aid of a clean, dry
mortar and pestle. Pour the
solution in a stopper bottle and
store for 30 days in a dark place,
shaking it periodically during this
period. Filter before use. Fill a
dropper bottle for use at the lab