Sysmex XN1000 versus Manual Method in Leukopenic Blood Samples

Abstract

Introduction: Complete Blood Cell (CBC) and differential leukocyte tests are one of the most common haematology laboratory investigations. Immature Granulocytes (IGs) form a part of extended leukocyte differential count and is considered as a promising tool for screening and early detection of bacteraemia. Differential leukocyte analysis provides information regarding the underlying pathologic process. Manual method of performing these counts is labor-intensive, time-consuming especially in leukopenic blood samples, lacks reproducibility and objectivity and therefore suffers from increased inter observer variation. Automated counts provided by the haematology analysers on the other hand are supposed to be more precise, objective and help to reduce the Turnaround Time (TAT). Aim: Comparison of Differential Leukocyte Count (DLC) and IG flagging by automated haematology analyser XN1000 with findings of manual method in leukopenic blood samples. Materials and Methods: The study included 346 patients considering the inclusion and exclusion criteria. CBC analysis was done using Sysmex XN1000. All leukopenic samples enumerated by the analyser were included and peripheral smears were made for each of them. Manual counts were correlated with cell counter counts. Statistical analysis was done using linear regression and correlation analysis. Mean counts were compared using Student's t-test. Pearson’s correlation coefficient and regression analysis was used for correlation studies. Bland-Altman plot analysis was also performed to compare the two measurement techniques. Results: Correlation coefficient for neutrophils, lymphocytes, eosinophils, monocytes and basophils proportional counts were 0.998, 0.992, 0.996, 0.771 and 0.570 respectively; and for absolute counts 0.999, 0.994, 0.996, 0.825 and 0.585 respectively. IG proportional and absolute counts correlation coefficients were 0.898 and 0.908 respectively. Sensitivity was 97.30%, specificity 91.91% and efficiency 92.49% for IG flagging. Conclusion: Strong positive correlation was observed between automated and manual neutrophil, lymphocyte, eosinophil, monocyte and IGs proportional and absolute counts. Basophil showed moderate degree of correlation for both proportional and absolute counts. IG flagging by Sysmex XN1000 showed high sensitivity, specificity and efficiency.Thus, automation seems to be a suitable, reliable and practical option for leukopenic blood samples keeping in view the results obtained by this analyser.

Keywords

• differential leukocyte count
• haematology cell counters
• leukopenia