Fragmented Red Cells Reference Range For The Sysmex Xn (R)-Series Of Automated Blood Cell Counters

Introduction: Fragmented red cells (FRCs) are a new parameter determined automatically by the latest generation of blood cell counters. FRC counts may be of interest as they may reflect schistocyte counts measured on a stained peripheral blood smear observed under the microscope. However, FRC counts depend on the technical procedure used to detect them so that reference ranges are device dependent. The XN-9000 (R) is one of the latest models from the Sysmex series of analysers.Material, methods and results: We aimed to establish a reference range for FRCs based on 1366 normal patient samples. The mean +/- SD was 0.14 +/- 0.35% and the median was 0% (95% confidence interval of the mean: 0.12-0.16%). We observed that the percentage of red blood cells with <17 pg of haemoglobin content (Hypo-He) was correlated to an FRC increase and that flagged results relating to red blood cells, reticulocytes or platelets might have presented with artefactually increased FRCs.Conclusion: The FRCs reference range (healthy subjects) should be useful for laboratory staff for selecting which blood smears to check optically.