Evaluation of Biologic Sources of Variation of Leukocyte Counts and Other Hematologic Quantities Using Very Precise Automated Analyzers

Abstract

Statland, Bernard E., Winkel, Per, Harris, Steven C., Burdsall, Mary J., and Saunders, Alex M.: Evaluation of biologic sources of variation of leukocyte counts and other hematologic quantities using very precise automated analyzers. Am J Clin Pathol 69: 48–54, 1977. The authors determined mean day-to-day (daily over five days), mean week-to-week (weekly over five weeks) and mean hour-to-hour (800 h, 1100 h, 1400 h) physiologic intra-individual variation of concentration values of leukocyte cell types, platelet count, and erythrocyte values (hematocrit, hemoglobin) for a group of 20 healthy adult volunteers. Total leukocyte counts and concentration values of leukocyte cell types were determined in duplicate on the Hemalog-D™ Automated Leukocyte Differential Cell Counter to minimize analytic variation. The data sets were analyzed according to an. analysis of variance model. The mean physiologic hour- to-hour and week-to-week intra-individual Variations in terms of % coefficient of variation included: hemoglobin, 2.5, 2.2; hematocrit, 2.6, 2.7; platelets, 1.6, 6.6; total leukocyte count, 9.4, 15.7; neutrophils, 12.9, 26.0; lymphocytes, 10.3, 13.2; monocytes, 18.6, 19.3; eosinophils, 19.9, 26.9; basophils, 7.4, 15.0; large unstained cells, 13.7,16.0; “high-peroxidase” cells, 32.7, 25.7. Hour-to-hour variation was partitioned into random diurnal variation, group-consistent diurnal variation, and subject-specific unique individual variation. Subject-specific diurnal variation contributed greatly and statistically significantly to total diurnal variation for many of the leukocyte cell types—especially in the case of eosinophils, where it represented more than half of total diurnal variation.