Reticulocytes

Abstract

In an effort to adapt the reticulocyte stain for use with oxalated venous blood and incorporate it in our uniform system of hematologic methods, 1 7 methods of reticulocyte staining in current use were tried. None proved wholly satisfactory. Experiment showed that increasing the time of exposure or increasing the concentration of the dye increased the number of reticulocytes found. It was also found that the presence of 2 mg. of potassium oxalate per cc. of blood did not alter the reticulocyte count.

The following procedure was found to give uniformly good stains with the maximum number of reticulocytes in a given blood:

Mix equal parts (5 drops) of oxalated venous blood 1 (or fresh blood) and 1% brilliant cresyl blue in 0.85% NaCl solution in a small test tube and allow to stand one minute or more. Mix and make a thin smear. This may be counted when dry, or counter-stained with Wright's stain. Count all the red cells (preferably with a hand tally) in an oil immersion field and then count all the reticulocytes in that field. Move to an adjacent field and repeat until 1000 red cells have been counted. If the count is more than 5%, only 500 cells need be counted. The counterstain is necessary if the slide is to be kept for more than 48 hours.

This method has many advantages. It is very simple and convenient and consistently gives a higher reticulocyte count than the other methods tried. The stain keeps indefinitely and need not be filtered before using. The oxalated blood may stand for as long as 48 hours before the count is made. Overstaining does not occur even though the smears are not made until 2 hours after the stain and blood are mixed.