Hematology instruments don’t speak the same language: a comparison study between flagging messages of sysmex XN-1000 and alinity H

Abstract Objectives While manual review is the gold standard, automated hematology analyzers are increasingly used. This study assessed the efficiency of white blood cell (WBC)-related flagging messages from the Sysmex XN-1000 and Alinity hq analyzers compared to peripheral blood smear (PBS) findings and evaluated their inter-platform agreement. Methods K 3 EDTA blood samples from hospitalized patients were analyzed using the Sysmex XN-1000. Samples triggering a morphology flag were reanalyzed on the Alinity hq, with PBS reviewed per CLSI protocol H20-A2-2007. Results Of 5530 samples, 196 had morphology-related flags requiring PBS review. Sysmex flagged 144 samples with leukocyte-related messages; Alinity flagged 120. The positive predictive value (PPV) for the Left Shift flag was 100 % for Sysmex and 77.5 % for Alinity; for Immature Granulocytes, it was 19.4 % for Sysmex and 94.6 % for Alinity. The Blast Flag’s PPVs were 9.3 % for Sysmex and 17.9 % for Alinity. Left Shift specificities were high (>94 %), but sensitivities varied. Sysmex showed 100 % sensitivity for the Blast flag but moderate specificity (53 %), while Alinity performed well (77–82 %). Agreement between platforms ranged from poor to good. Conclusions Tailored SOPs are crucial for optimizing laboratory workflow based on different flagging performances. Understanding each analyzer’s strengths and limitations improves interpretation and workflow management.