Antech's Research Department initiated a study to assess whether discrepancies exist when the total and differential WBC counts are determined by three different methods (Unopette, Estimate and Cell Dyne). With the Becton Dickinson Unopette microcollection system, leukocytes are counted in diluted blood placed in a hemacytometer. With the Estimate method, the number of leukocytes per 40 × objective, from at least five fields, are counted on a Wright's stained blood smear. The average number of leukocytes is then multiplied by 1000 to make an estimated total white cell count. The Abbott Cell-Dyne 3500 automated CBC analyzer uses a laser beam and measures the light scattered by the cells to give the total and differential leukocyte count.

Statistical analysis revealed no clinically significant difference between cell counts performed by the Estimate or Unopette methods. However, the Cell-Dyne automated instrument produced a significantly higher total leukocyte count as compared to the average result of the other two methods. Based on these findings, the Estimate or Unopette methods are recommended as an acceptable procedure for avian and reptile WBC counts.