Beyond Analytical Agreement: Integrating Analytical Performance and Algorithm-Assisted Morphological Interpretation in a Comparative Evaluation of the Mindray BC-7800/BC-7900 and Sysmex XN-9100 Hematology Platforms

Background/Objectives: Modern automated hematology analyzers combine quantitative cell counting with proprietary algorithms for automated morphological interpretation. While analytical validation traditionally focuses on measurement agreement, less attention has been paid to the evaluation of algorithm-assisted morphological interpretation. This study compared the analytical performance and automated morphological flagging of the Sysmex XN-9100 and Mindray BC-7800/BC-7900 platforms under routine laboratory conditions. Methods: A total of 183 peripheral blood samples collected between October 2025 and February 2026 were analyzed in parallel using both platforms. The study population included healthy individuals and patients with hematological and non-hematological disorders. Analytical agreement for complete blood count (CBC) and leukocyte differential parameters was assessed using Passing–Bablok regression and Bland–Altman analyses. Automated morphological flagging was evaluated in 157 samples using expert optical microscopy as the reference standard. McNemar’s test, Cohen’s kappa coefficient, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated. Results: Excellent agreement was observed for the principal CBC parameters, including white blood cell count, red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, and platelet count (correlation coefficients: 0.981–1.000), with minimal proportional bias. Greater variability was found for monocytes, eosinophils, and basophils, particularly at low cell concentrations. Although analytical performance was highly comparable, the two platforms showed different morphological flagging profiles. Both analyzers achieved high negative predictive values (>90%), while differences in sensitivity and specificity across individual flag categories reflected distinct algorithm-assisted classification strategies. Agreement with expert microscopy ranged from fair to moderate for most pathological flags. Conclusions: The Mindray BC-7800/BC-7900 and Sysmex XN-9100 demonstrated excellent analytical agreement for routine CBC testing. However, comparable analytical performance did not necessarily correspond to identical automated morphological interpretation. These results indicate that evaluation of modern hematology analyzers should include both analytical performance and agreement between automated flags and expert microscopy.