On the Label-free Analysis of White Blood Cells by Holographic Quantitative Phase Imaging Flow Cytometry

This study presents an innovative methodology to analyze a blood sample from a healthy donor, providing a quantitative characterization of white blood cells (WBCs). It aims to evaluate the effectiveness of holographic quantitative phase imaging (QPI) flow cytometry (FC) in examining phase-contrast maps at the cellular level, thereby enabling the identification and classification of granulocyte types. Additionally, we demonstrate that an unsupervised method can differentiate granulocyte sub-types, i.e., neutrophils and eosinophils. The results instill strong confidence in the potential future use of QPI FC for liquid biopsies and/or for assessing the heterogeneity of WBCs and, more broadly, to facilitate label-free blood tests.