(7) If nucleated erythrocytes are present, the count is corrected by the
observed count X 100
corrected count =
100 + percent nucleated erythrocytes
The percent nucleated erythrocyte is obtained from the differential count, which is
discussed in another subcourse.
g. Normal Values.
Adults (both sexes): 4,500-11,500 WBCs per cu mm.
Childhood: 6,000-14,000 WBCs per cu mm.
Birth: 9,000-30,000 WBCs per cu mm.
h. Unopette Procedure for White Blood Cell Count.
Follow procedure described in para 2-5 for blood dilution.
Prepare diluted specimen for count.
(a) Mix diluted blood by inverting reservoir to resuspend cells.
(b) Convert to dropper assembly by withdrawing pipet from reservoir
and reseating securely in reverse position.
(c) To clean capillary more, invert reservoir, gently squeeze sides, and
discard first three to four drops.
(d) Carefully load hemacytometer with diluted blood by gently
squeezing sides of reservoir to expel contents until chamber is properly filled.
(e) Place hemacytometer in moisture chamber, let stand for 3 to 5
minutes (10 minutes for platelets) to allow cells to settle.
Counting and calculation of leukocytes.
(a) Under 100X (low power) magnification, count leukocytes in all nine
large squares of the counting chamber.
(b) Add 10 percent of count to total number of cells counted. This step
simplifies the calculation that actually entails dividing the number of cells by the number
of squares counted and multiplying by 10 to correct for the depth of the chamber.