Utility of Differential White Cell Count and Cell Population Data for Ruling Out COVID-19 Infection in Patients With Community-Acquired Pneumonia

Time-dependent changes in cell population data obtained using Sysmex XN-series hematology analyzer in bacterial infections

BACKGROUND

Time-dependent changes in cell populations during acute bacterial infections remain unclear. We assessed time-dependent changes in fluorescent light intensity of the neutrophil area (NE-SFL) and fluorescent light distribution width index of the neutrophil area (NE-WY) and their association with sepsis and bacteremia.

METHODS

Patients with acute bacterial infections were enrolled in this prospective, observational cohort study. Blood samples were collected from all patients at the onset of bacterial infections (day 0) and on days 1 and 3. Microbiological evaluation included the examination of blood bacterial load using PCR. Cell population data were assessed using an automated hematology analyzer (Sysmex series XN-2000).

RESULTS

Forty-three participants with acute bacterial infections were enrolled in the study. Twenty-five participants developed definite sepsis. All the participants improved after the onset of infection. NE-WY levels showed significant time-dependent changes in participants with sepsis, peaking on day 0 and significantly decreasing until day 3, whereas these changes were not statistically significant for NE-SFL. A significant correlation with the Sequential Organ Failure Assessment score was observed with NE-WY and NE-SFL in the entire cohort on days 0 and 1. However, only NE-WY showed a significant correlation with blood bacterial load on days 0 and 1.

CONCLUSION

This study demonstrated that NE-WY elevation in sepsis peaked earlier than NE-SFL, which may partly reflect the early bacterial invasion into circulation. These findings advocate caution in interpreting cell population data values as sepsis biomarkers and propose the potential of NE-WY as a therapeutic indicator.

Reference intervals of cell population data parameters in Sysmex XN-Series and its patterns of changes from early adulthood to geriatric ages in South Korea

INTRODUCTION

Cell population data (CPD) parameters may be putative biomarkers for the screening of various diseases including some infections and myelodysplastic syndrome. This study aimed to establish the age- and sex-specific reference intervals (RIs) for the CPD parameters in the Korean population.

METHODS

The reference population for the RIs of CPD parameters comprised 124 856 subjects aged 20-99 years. CPD parameters were obtained from Sysmex XN-2000 (Kobe, Japan) datasets from 17 health promotion centers in 13 South Korean cities. We determined significant partitions for age and sex, and calculated RIs according to Clinical and Laboratory Standards Institute C28-A3 guidelines.

RESULTS

The side scattered light intensity in the neutrophil area and the lymphocyte area did not require sex-related partitioning except in those over the age of 50, among whom the lower limit (LL) and upper limit (UL) were lower in females. However, the side scattered light distribution width in the lymphocyte area required age- and sex-related partitioning, in which LL and UL were higher in females. The LL and UL of the fluorescent light distribution width were higher in males in the neutrophil area and higher in females in the lymphocyte area, but age-related partitioning was not required. The forward scattered light intensity in the neutrophil area, lymphocyte area, and monocyte area did not require age-related partitioning in males.

CONCLUSION

This study has determined comprehensive age- and sex-specific RIs for CPD parameters, which could help to prove the clinical significance of these parameters in the Sysmex XN-2000.