Adjustments Made To The Q-Flags Affect The Performance Of The Flags Generated By The Imi Channel

Introduction: IMI-DC (immature information-direct current) is a useful index for efficient morphologic classification of cells. This study assessed the usefulness of IMI-DC thresholds to retain less than 5% false negative rate on automated cell counters. Methods: In total, 526 blood samples supplemented with EDTA-K2 (1.8 mg/mL) were analyzed on Sysmex XE2100. Then, 5 WBC-specific flags including blasts, immature granulocytes, left shift were verified by manual slide review. Laboman EasyAccess 4.2.44 was used for data analysis and measuring efficiency. False-negatives were counted by standard microscopy following the laboratory's standard operating procedure. Optimized IMI-DC thresholds were assessed by receiver operating characteristic (ROC) curve through maximized Yl. The efficiency of the optimized IMI-DC thresholds was verified by 200 additional samples. Results: The 526 samples examined by the Laboman software showed 63.40% positive predictive value (PPV), 89.81% negative predictive value (NPV), 82,13% efficiency, 10.65% false-positives, 7.22% false-negatives and 29.09% review rate. Maximized Youden index (YI) altered the false negative rate to 3.5%, PPV to 64.15%, NPV to 95.24%, efficiency to 87.00%, and false-positive to 9.5%. Finally, review rate was reduced from 29.09% to 26.5%. Discussion: IMI-DC is associated with false negative rate in automated cell counters. A low false negative rate helps improve the accuracy of automated cell counters.