Performance evaluation of the automated nucleated red blood cell enumeration on Sysmex XN analyser

INTRODUCTION: Presence of peripheral blood nucleated red blood cell (NRBC) is associated with pathological conditions and leads to the overestimation of white blood cell count in automated haematology analysers (HA). The authors evaluated NRBC enumeration by a new HA Sysmex XN (XN) to demonstrate the precision and comparability to manual count (MC) at the various NRBC values. METHODS: Specimens with initially NRBC positive were included. For precision assessment, 8 levels of NRBCs were repeatedly analysed. For comparison study, 234 specimens were analysed by both XN and MC. RESULTS: For precision study, the percentage of coefficient of variation ranged from 14% to 45.6% and 1.2% to 4.4% for MC and XN, respectively. For comparison study between XN and MC, NRBCs ranged from 0% to 612.5%. Regression analysis demonstrated an r(2) of 0.98. The mean bias of 14.1% with 95% limits of agreement between -48.76% and 76.95% was found. The NRBC counts from XN appeared to be more in accordance with MC when the NRBCs were lower than 200% with the concordance rate of 94.2%. CONCLUSION: The automated NRBC enumeration by XN was precise and could replace the traditional MC, especially for the specimens with NRBCs lower than 200%.