New erythrocyte parameters derived from the Coulter principle relate with red blood cell properties-A pilot study in diabetes mellitus.

In routine hematological instruments, blood cells are counted and sized by monitoring the impedance signals induced during their passage through a Coulter orifice. However, only signals associated with centered paths in the aperture are considered for analysis, while the rejected measurements, caused by near-wall trajectories, can provide additional information on red blood cells (RBC), as recent publications suggest. To assess usefulness of two new parameters in describing alterations in RBC properties, we performed a pilot study to compare blood samples from patients with diabetes mellitus (DM), frequent pathological condition associated with impairment in RBC deformability, versus controls.

Red blood cell rheology during a complete blood count: A proof of concept.

Counting and sizing blood cells in hematological analyzers is achieved using the Coulter principle. The cells flow in a micro-aperture in which a strong electrical field is imposed, so that an electrical perturbation, called pulse, is measured each time a cell crosses the orifice. The pulses are expected to contain information on the shape and deformability of Red Blood Cells (RBCs), since recent studies state that RBCs rotate and deform in the micro-orifice.

Detecting cells rotations for increasing the robustness of cell sizing by impedance measurements, with or without machine learning.

The Coulter principle is a widespread technique for sizing red blood cells (RBCs) in hematological analyzers. It is based on the monitoring of the electrical perturbations generated by cells passing through a micro-orifice, in which a concentrated electrical field is imposed by two electrodes. However, artifacts associated with near-wall passages in the sensing region are known to skew the statistics for RBCs sizing.

Numerical simulation of deformable particles in a Coulter counter.

In Coulter counters, cells counting and volumetry are achieved by monitoring their electrical print when they flow through a sensing zone. However, the volume measurement may be impaired by the cell dynamics, which may be difficult to control. In this paper, numerical simulations of the dynamics and electrical signature of red blood cells in a Coulter counter are presented, accounting for the deformability of the cells.

Fast Magnetic Field-Enhanced Linear Colloidal Agglutination Immunoassay.

We present the principle of a fast magnetic field enhanced colloidal agglutination assay, which is based on the acceleration of the recognition rate between ligands and receptors induced by magnetic forces. By applying a homogeneous magnetic field of 20 mT for only 7 s, we detect CRP (C-reactive protein) in human serum at a concentration as low as 1 pM for a total cycle time of about 1 min in a prototype analyzer. Such a short measurement time does not impair the performances of the assay when compared to longer experiments.

Wavelength encoding technique for particle analyses in hematology analyzer.

The aim of this study is to combine multiple excitation wavelengths in order to improve accuracy of fluorescence characterization of labeled cells. The experimental demonstration is realized with a hematology analyzer based on flow cytometry and a CW laser source emitting two visible wavelengths. A given optical encoding associated to each wavelength allows fluorescence identification coming from specific fluorochromes and avoiding the use of noisy compensation method.