True volumetric counting of CD34+ cells using flow cytometry

Area of Science:

• Hematology
• Flow Cytometry
• Stem Cell Analysis

Background:

• CD34+ cell counting is crucial for predicting mobilized peripheral blood stem cell yield.
• Traditional flow cytometry methods using microbeads face challenges like the vanishing counting bead phenomenon.
• Most flow cytometers lack volumetric counting capabilities found in hematology analyzers.

Purpose of the Study:

• To evaluate direct true volumetric counting of CD34+ cells as an alternative to bead-based methods.
• To compare CD34+ cell enumeration using volumetric and non-volumetric flow cytometry systems.
• To assess the accuracy and agreement of volumetric counting for rare cell analysis.

Main Methods:

• Comparison of CD34+ cell counts between non-volumetric (FC500) and volumetric (Attune NxT) flow cytometers.
• Utilized direct true volumetric counting under a continuous flow pump.
• Employed linear regression and Bland-Altman analysis to assess method agreement and accuracy.

Main Results:

• No statistically significant differences were found between CD34+ cell counts obtained using beads on different systems or using volumetric vs. non-volumetric methods on the same system.
• Linear regression confirmed the accuracy of both volumetric and non-volumetric counting methods.
• Bland-Altman analysis demonstrated good agreement between the volumetric and non-volumetric approaches.

Conclusions:

• CD34+ cell enumeration using a volumetric system is comparable to current bead-based counting systems.
• Volumetric counting offers advantages in simplifying sample preparation and reducing analysis subjectivity.
• This method presents a viable alternative for accurate CD34+ cell enumeration in clinical settings.