(2) Crenated erythrocytes and rouleaux formation make an accurate count
difficult to perform.
Stain precipitated on erythrocytes causes them to appear as
Dirty slides cause uneven spreading.
(5) The dye solution should have adequate time to penetrate the cell and
stain the reticulum.
(1) Reticulocytes are nonnucleated erythrocytes that exhibit blue reticulum
strands within their cytoplasm when stained supravitally. When stained only with
Wright's stain, they are buff-pink in color and larger and darker than erythrocytes.
(2) Reticulocytes serve as an index of the activity of the bone marrow in
blood regeneration. As such, these counts are of value in following anti-anemia
therapy. Satisfactory response to therapy is evidenced by an increase of reticulocytes
in the peripheral blood. Increased reticulocyte counts also occur whenever there is
rapid bone marrow activity as in leukemia or blood regeneration associated with
hemorrhage or hemolysis. Decreased reticulocyte counts occur in conditions in which
the bone marrow is not producing adequate red blood cells, such as aplastic anemia.
(3) Several methods for staining and counting reticulocytes are in common
use. Compared to the use of alcoholic solutions of dye, methods employing saline
solutions of new methylene blue can give slightly higher values for reticulocytes. For
comparative studies, the same method should be used throughout the work.
(4) Precipitated stain is often confused with reticulum but can be recognized
by its presence throughout the smear and apart from the red cells. Precipitation can be
eliminated as a source of error by frequently filtering the stain.
(5) An alternate method of counting reticulocytes utilizes the Miller disk that
is placed inside the microscope eyepiece. This disc consists of 2 squares as shown
below in figure 5-2. The area of the smaller square (B) is a tenth that of square A.
Therefore, if there are 40 red cells in square A, there should be four red cells present in
square B. When employing this method to count reticulocytes, the red cells in square B
are counted in successive fields on the slide, until a total of 500 red cells have been
counted. At the same time, the reticulocytes in square A are enumerated. At the
completion of the count, theoretically, the reticulocytes obtained in this way are divided
by 50, in order to obtain the percent reticulocytes present in the blood.