Efficiency of Leukocyte Differential Using Flow Cytometry with CytoDiff in Different Workflows

Background To set up the review criteria for flow cytometry with CytoDiff (FCC) and evaluate the efficiency of different workflows using combinations of FCC with a hematology analyzer and microscopy. Methods Leucocyte differentials of the samples from 995 clinical specimens and 278 specimens from healthy donors were analyzed using a hematology analyzer, FCC, and microscopy. Results The correlations between the hematology analyzer, FCC, and microscopy were good for neutrophils, lymphocytes, and monocytes, but not in the case of basophils (r = 0.464, 0.358, 0.33) and eosinophils (r = 0.69, 0.67, 0.621). As a reference method of WBC differential using microscopy, the threshold of blasts for FCC was defined by a ROC curve at 1% (specificity 97.9%, sensitivity 97.5%, AUC 0.989). The optimal cutoff of immature granulocytes for FCC was 1% (specificity 85.8%, sensitivity 76.5%, AUC 0.866). The optimal cutoff of lymphocytes, neutrophils, and monocytes were 50%, 85% and 12%, respectively. According to the review criteria, the workflow of CBC after FCC and then microscopy had the highest sensitivity (97.07%), lower false negative rate (2.93%), and higher accuracy (80.3%) compared with others. Conclusions Our study integrated FCC into a WBC differential workflow in a routine laboratory and, for the first time, demonstrates the efficiency of different workflows. It can be used for reference in the selection of different hematology workflows.