(1) Fuchs-Rosenthal or levy hemacytometer is preferable to a standard
counting chamber since its greater volume (4.0 X 4.0 X 0.2 mm) allows for counting of
more cells, thereby reducing the statistical error. Counting two of these chambers is
equivalent in accuracy to seven standard chamber counts.
(2) In eosinopenia, it is necessary to set up more chambers to provide an
optional number of cells to be counted.
The eosinacetone diluting fluids are unsatisfactory and should not be
(4) Estimation of eosinophils on a stained blood smear is too inaccurate for
use because of poor cellular distribution.
(5) The propylene glycol in Pilot's solution renders the erythrocytes invisible,
and the sodium carbonate causes lysis of all the leukocytes except the eosinophils.
The phloxine stains the eosinophils.
(6) In the Thorn test an eosinophil count must be made prior to the initiation
of the test proper. This establishes the patient's total eosinophil count, to which the
response of the adrenal cortex to adrenocorticotropic hormone (ACTH) can be judged.
The ACTH is then injected and, at an interval of 4 hours, another eosinophil count is
made. The interpretation of this test is as follows:
Normal--approximately a 50 percent drop in eosinophils.
Cushing's disease (hyperadrenalism)--0-30 eosinophils per cu mm.
Addison's disease (hypoadrenalism) no change in eosinophil count.
(7) Nasal smears are also submitted for eosinophil evaluation. These
smears are stained with Wright's stain and examined for the presence of eosinophils.
g. Normal Value. Normal value: 150-300 eosinophils per cu mm.
a. Principle. Nonnucleated immature erythrocytes contain nuclear remnants of
RNA and the cell is known as a reticulocyte. To detect the presence of this RNA, the
red cells must be stained while they are still living. This process is called supravital
staining. With supravital staining, the RNA appears as a reticulum within the red cell.