A-147 Using the Immature Granulocytes (IG) of White Blood Cells as a Reference for Sepsis Diagnosis

Abstract Background Sepsis is a systemic inflammatory response syndrome (SIRS) caused by bacterial infection. It progresses rapidly and has a high mortality rate. Early and accurate diagnosis is crucial for reducing sepsis mortality. Common clinical diagnostic methods, such as blood culture or procalcitonin (PCT), have limitations in terms of time and sensitivity, posing significant challenges for clinical diagnosis and treatment. Immature Granulocytes (IG) include early immature cells of neutrophils, such as promyelocytes, metamyelocytes, and myelocytes, which increase significantly during acute inflammatory responses like infection or sepsis. Using the Sysmex XN series hematology analyzer, IG% (relative white blood cell percentage) and IG# (absolute count) can be quickly and automatically quantified, providing a potential tool for early sepsis diagnosis. This study not only investigates the correlation between IG and sepsis but also defines reference ranges for IG% and IG# in the Taiwanese population, providing a basis for sepsis diagnosis and application. Methods 1.Equipment: Sysmex XN series hematology analyzer. 2.Sample Source: Blood samples from 420 emergency patients suspected of sepsis and 317 health patients. 3.Sample Preparation: Purple-top tubes containing K2EDTA anticoagulant. 4.Sepsis Determination Standard: Positive blood culture. 5.Analysis Methods: Microsoft Excel and SPSS software. Results The biological reference range for healthy individuals was established using samples from health patients. The mean ± 2SD for IG% was 0.25 (0-0.64), with the 97.5th percentile at 0.50. The mean ± 2SD for IG# was 15.37 (0-50.22), with the 97.5th percentile at 32.92. The reference values for the healthy Taiwanese population were set at IG% of 0.5% and IG# of 33 cells/µL. Comparing these reference values with positive blood culture cases from emergency patients suspected of sepsis, 90% of cases had IG# greater than 33 cells/µL, showing a high correlation with sepsis determination standards. Conclusion IG% or IG#, analyzed using the CLSI C28 recommended Z-Test, showed results less than 3, indicating no need for separate reference ranges for males and females. This biological reference range is specific to the Taiwanese population and may vary by region or ethnicity. Using the XN series hematology analyzer for IG analysis, as an adjunct parameter to the existing routine CBC test, does not require additional reagent costs. The report can be issued simultaneously with the CBC report, providing results within 30 minutes for emergency patients. This aids in the triage of emergency patients and provides clinicians with a basis for sepsis diagnosis, offering potential value for rapid clinical testing and screening.