Reference interval for immature platelet fraction on Sysmex XN hematology analyzer: a comparison study with Sysmex XE-2100

Background: Recently introduced hematology analyzer, the Sysmex XN modular system (Sysmex, Kobe, Japan), has newly adopted a florescent channel to detect platelets and immature platelet fraction (IPF). This study aimed to establish new reference intervals for %-IPF and absolute number of IPF (A-IPF) on Sysmex XN. Platelet counts, %-IPF, and A-IPF were also compared between Sysmex XN and XE-2100 systems (Sysmex). Methods: Except outliers, blood samples from 2104 healthy individuals and 140 umbilical cord blood were analyzed using both Sysmex XN and XE-2100. The results of two systems were compared using Bland-Altman plot. The reference intervals for %-IPF and A-IPF were defined using non-parametric percentile methods according to the Clinical and Laboratory Standard Institute guideline (C28-A3). Results: The platelet counts, %-IPF, and A-IPF showed non-parametric distributions. The mean difference between Sysmex XN and XE-2100 in healthy individuals revealed a positive bias in platelets (+8.0x10(9)/L), %-IPF (+1.2%), and A-IPF (+3.0x10(9)/L). The reference intervals for %-IPF and A-IPF on Sysmex XN were: 1.0%-7.3% and 2.49-15.64x10(9)/L in healthy individuals; and 1.0%-4.4% and 2.94-12.82x10(9)/L in umbilical cord blood. Conclusions: This large-scale study demonstrates a clear difference of platelet counts and IPF between Sysmex XN and XE-2100. The new reference intervals for IPF on Sysmex XN would provide fundamental data for clinical practice and future research.