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Am J Clin Pathol. 1994 Jan;101(1):85-90.

Evaluation of automated reticulocyte counts and their reliability in the presence of Howell-Jolly bodies.

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Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455.


An automated reticulocyte procedure using a flow cytometer and the fluorescent dye thiazole orange was evaluated for clinical use. The mean reticulocyte count on 118 hematologically healthy adults was 1.56% (standard deviation [SD] 0.54), with virtually no difference in percentage between women and men. The mean absolute values were 68.4 x 10(9)/L (SD 24.6) and 75.7 x 10(9)/L (SD 27.2), respectively. When compared with the standard microscopic technique, the automated method showed excellent correlation (r = 0.98) and greatly improved precision (coefficient of variation [CV] 4.1%) over the manual method (CV 22.8%). Preanalytic storage of blood samples at 4 degrees C for up to 48 hours did not significantly affect results, nor did varying the incubation time of diluted samples from 1/2 to 2 hours. In a group of patients with appreciable numbers of Howell-Jolly bodies, automated reticulocyte counts were spuriously elevated. The difference between the manual and automated counts on these patients approximated the percentage of Howell-Jolly bodies observed on their Wright-Giemsa stained blood smears.

[Indexed for MEDLINE]

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