Multiply this figure by 1000 to get total leukocyte count.
TOTAL EOSINOPHIL COUNT
a. Principle. A sample of blood is diluted with a solution that selectively stains
the eosinophils and eliminates all other leukocytes and erythrocytes from view.
Following mixing, the specimen is introduced into the counting chamber and the number
of eosinophils in a known volume of blood is counted.
b. Reagent. Pilot's Solution: Add 50 ml propylene glycol, 40 ml distilled water,
and 1.0 ml sodium carbonate (10 percent aqueous) to a 150-ml beaker. Mix well and
filter. Add 10 ml of phloxine (1 percent aqueous) just prior to use. The addition of 10
units of heparin to this solution prevents clumping of cells.
(1) Draw capillary (or venous) blood to the "1.0" mark in each of two white
cell diluting pipets.
Draw Pilot's solution to the "11" mark of each pipet.
(3) Mix by gently shaking the pipets for 30 seconds. Prolonged and harsh
shaking will tend to cause rupturing of the eosinophils.
Expel the cell-free liquid from the capillary portion of the pipets.
(5) Using one pipet, charge both chambers of a hemacytometer and with
the other pipet charge both chambers of the second hemacytometer.
(6) Allow both hemacytometers to stand for 15 minutes to permit staining of
the eosinophils. To prevent evaporation, the hemacytometers are placed on a damp
towel and covered with Petri dish covers.
(7) Under low-power magnification, count the red-stained eosinophils in the
entire ruled area (9 sq mm) each of the four chambers (a total area of 36 sq mm). The
chamber has a depth of 0.1 mm so the total vo1ume is 3.6 cu mm.
Number of eosinophils counted X dilution (10)
Number of eosinophils =
Per cu mm
e. Source of Error. See paragraph 5-2e.