Flow-cytometric lymphocyte subsets enumeration: comparison of single/dual-platform method in clinical laboratory with dual-platform extended PanLeucogating method in reference laboratory.

Abstract

Objectives: To improve the accuracy of lymphocyte subsets counts, a traceable dual-platform extended PanLeucogating method (DPP) of absolute cell counts of lymphocyte subsets was introduced, and consistency was evaluated by comparing conventional single/dual-platform method with DPP.

Methods: The DPP for absolute lymphocyte subsets counts was established by multiplying the percentage of lymphocyte subsets in total white blood cells (WBC) measured by flow cytometer with the total WBC counts. DPP-R was defined as the use of the total WBC counts measured in reference laboratory that was traceable to reference method recommended by International Council for Standardization in Hematology (ICSH). When the total WBC counts measured in clinical laboratory were utilized, it was designated as DDP-C. The comparability of conventional single/dual-platform method and DPP-R was assessed using a total of 566 peripheral blood samples. Additionally, the inter-laboratory precision of the single-platform and the dual-platform method was compared based on data from China National External Quality AssessmentScheme (China NEQAS).

Results: The results of the DPP-R exhibited a robust linear correlation with conventional single/dual-platform method (r=0.9909 to 0.9973). However, notable proportional differences existed. The mean biases between DPP-R and conventional single/dual-platform method ranged from -0.0116 to 0.0714 (×10⁹/L). According to China NEQAS data, the robust coefficient of variations in dual-platform group were comparable to, or even marginally lower than, that of the single-platform groups.

Conclusions: The DPP-R was valuable for achieving the traceability of absolute enumeration of lymphocyte subsets, exhibited a strong correlation with conventional single/dual-platform method and could serve as a reference standard for assessing the accuracy of such detection. However, there existed bias between DPP-R and conventional single/dual-platform method, thus manufacturers should provide explicit statements for traceability of beads and standardize beads gating procedures or aspired sample volume.