The Coulter DxH 800 hematology analyzer can determine leukocyte numerical parameters (total leukocyte counts and differentials). It also measures intrinsic biophysical properties of these cells in their near-native state. These morphologic measurements are known as cell population data (CPD).
To study, for the first time, the biological variations of morphologic parameters or CPD and reinvestigate numerical parameters using the newest Coulter hematology analyzer. Design.-Forty adult volunteers (21 women, 19 men) were included. All participants maintained their normal lifestyles. Blood samples were drawn in duplicate by a single experienced phlebotomist and analyzed within 2 hours using a single analyzer. Before each batch analysis, the instrument quality controls were performed using the same lots of reagents.
Within-subject (CV(I)) and between-subjects (CV(G)) biological variations for numerical parameters are smaller than previously reported. Cell population data have much smaller overall CV(I) and CV(G) compared to numerical parameters, suggesting that these parameters are less variable around the homeostatic set point intraindividually and interindividually. Index of individuality (ratio of CV(I)/CV(G)) for CPD was low. In addition, intraday and interday biological variations of all parameters are fairly constant.
These observations are clinically valuable. Data on CV(I) and analytical precision may be used to generate objective delta-check values for use in quality management. Comparing CV(I) and CV(G) on CPD may allow us to decide the utility of traditional population-based reference ranges. Documentation of CPD on biological variations is an essential prerequisite in the development of any new application clinically.