Validation of Automated Fragmented Red Cell Count by the Sysmex
XN
‐9000: Correlation With Microscopy and Impact of Microcytosis/Hypochromia
Xian Cai, Guiling Li, Hongying Tang, Jin Zhao, Fei Ma ABSTRACT
Introduction
This study aimed to evaluate the analytical performance and screening performance of fragmented red cell (FRC) enumeration by the reticulocyte (RET) channel of the Sysmex XN‐9000 automated hematology analyzer and to determine its correlation with manual microscopy with a specific focus on the confounding effects of microcytosis and hypochromia.
Methods
Peripheral blood samples from 209 patients with anemia who had positive FRC% flagged by the analyzer and 200 healthy individuals were analyzed. The FRC percentage (FRC%) was measured both by the automated analyzer and by standard manual microscopy. Statistical analyses, including correlation studies, receiver operating characteristic (ROC) curve, and Bland–Altman agreement analysis, were performed.
Results
The area under the ROC curve for instrument‐measured FRC% was 0.927, indicating potential diagnostic screening performance. Using manual microscopy as the reference method, the correlation coefficient for FRC% measured by the RET channel was 0.66, indicating a moderate correlation between the two methods. Bland–Altman analysis revealed a mean bias of −0.91% (limits of agreement: −4.61% to 2.79%) with 78.9% of instrument results reading higher than microscopy. The upper reference limit for FRC% in the healthy cohort was established at 0.17%.
Conclusion
The automated FRC% measurement on the XN‐9000 serves as an effective screening tool. However, confirmatory manual microscopic review remains essential for samples with positive automated results or those exhibiting abnormal MicroR% and Hypo‐He% values.