Flow cytometric enumeration of CD34+ hematopoietic stem cells: A comparison between single- versus dual-platform methodology using the International Society of Hematotherapy and Graft Engineering protocol

Background: Flow cytometric enumeration of CD34+ hematopoietic stem cells (HSC) is the reference point for undertaking apheresis and evaluation of adequacy for peripheral blood stem cell (PBSC) engraftment. Aims: To determine whether single platform correlates with dual platform methods in CD34+ enumeration using ISHAGE protocol. Methods: Retrospective analysis of CD34 Enumeration assays on both peripheral blood and PBSC product samples using Beckman Coulter FC500 Flow Cytometer. The t test and correlation study was used to study the difference between single and dual platform methods in CD34+ enumeration. Results: We present our data on 152 samples comprising 41 peripheral blood samples collected before apheresis procedure and 111 samples collected from PBSC product. We observed strong positive correlation between single and dual platform methods for CD34+ counts in peripheral blood sample (r = 0.92; P < 0.001) and PBSC product sample (r = 0.85; P < 0.001). Conclusion: In our study, both single versus dual platform had similar results in CD34+ cell counts. The single platform provides rapid results with ease of procedure. Errors with dual platforms are relatively common with respect to denominator. We recommend to use mean of total leukocyte count from two different hematology analyzer to minimize variation in dual platform.