The use of CellaVision™ DM96 in the verification of the presence of blasts in samples flagged by the Sysmex XE-5000

Introduction: The CellaVision (TM) DM96 is a digital pattern recognition system that classifies white blood cells. The aim of this study was to evaluate whether the CellaVision preclassification feature, without a subsequent re-classification, was a sufficient approach to follow up flags reported by Sysmex XE-5000. Methods: Pairs of blood smears from 400 samples reported with suspect flags were examined using conventional microscopy and the CellaVision features. The effect of pre- vs. re-classification, and intersmear and between-technologist variation, on blast counts was assessed using generalized linear mixed models (GLMM). Results: The GLMM analysis showed a significant difference between the blast counts of preclassification vs. re-classification (P = 0.009). The analysis showed no significant difference between duplicate smears (P = 0.621) or between technologists (P = 0.542). Preclassification showed blasts in 105 samples (26%), where the re-classification feature did not detect any blasts. Not a single sample that was re-classified as positive for blasts was preclassified as negative. Compared to manual microscopy, the sensitivity and specificity of the preclassification feature were 0.83 and 0.66, respectively. Conclusion: The preclassification feature alone is sufficient to verify the absence of blasts in flagged samples. When the preclassification feature detects blasts, the finding has to be verified or reclassified by an experienced technologist. However, the use of CellaVision (TM) DM96 in the follow-up of blast reports has to be questioned due to the finding of false-negative samples in the preclassification feature, but also after re-classification, compared to manual slide review.