N Context.-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).Objective.-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.Results.-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.Conclusions.-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.

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ObjectivesA significant number of researches have evidenced that occupational lead (Pb) exposure increased risks of cardiovascular disease. However, evidences about the potential effects of Pb on the cardiac conduction system are sparse and inconclusive. Besides, ryanodine receptors (RyRs) induced dysfunction of cardiac excitation contraction coupling which is considered to be one of the mechanisms in cardiovascular diseases. Therefore, we examined the association between occupational Pb exposure and ECG conduction abnormalities, as well as RyRs in Pb-induced ECG abnormalities.MethodsWe investigated 529 Pb smelter workers, and measured blood lead (BPb), zinc protoporphyrin (ZPP), ECG outcomes and RyR expression levels. Based on BPb levels, the workers were divided into three groups: the BPb not elevated group, the BPb elevated group and the Pb poisoning group. Descriptive and multivariable analyses were performed.ResultsCompared with the BPb not elevated group, the Pb poisoning group had a higher incidence of high QRS voltage, and a lower level of RyR1 gene expression (p<0.05). Further unconditional multivariable logistic regression analyses showed that high QRS voltage was positively related to BPb (OR=1.045, 95% CI 1.014 to 1.078) and inversely associated with RyR1 expression (OR=0.042, 95% CI 0.002 to 0.980) after adjusting for potential confounders. In addition, multiple linear regression analyses showed that the QTc interval was positively associated with ZPP (β=0.299, 95% CI 0.130 to 0.468) after adjusting for potential confounders.ConclusionsOur study provided evidences that occupational exposure to Pb may be associated with worse ECG outcomes (high QRS voltage), which might be related to decreased levels of RyR1.