As a peripheral blood routine detection instrument, the blood cell analyzer can automatically analyze blood cells in a certain volume of whole blood, mainly including blood cell counting and classification, hemoglobin measurement, and related parameter calculation.
The update and replacement of blood cell analyzers have been closely following the progress of biotechnology, evolving from three grouping functions to five classifications. Its detection principle has gradually expanded from the most classic electrical impedance Coulter technology to volume conductivity light scattering VCS technology, multi angle polarized light scattering MAPSS technology, double sheath flow force continuous system DHSS technology, and flow cytometry technology relying on laser scattering combined with fluorescence staining or cytochemical staining. At present, flow laser scattering combined with fluorescence staining technology has great advantages in both parameter and evaluation of blood cell analysis. Below, I have compiled some of the techniques, scatter plots, and histograms used in the commonly used Xisen Meikang fully automatic blood cell analyzer to share with everyone.
The basic detection principle of blood cell analyzer
01
Principle of Electrical Impedance
The principle of electrical impedance (Kurt's principle) is that blood cells, as a physical particle, generate resistance when passing through an electric field, resulting in pulse waves. The number of pulse waves reflects the number of blood cells; The pulse wave size produced by blood cells of different volume sizes also varies, and different blood cells can be classified and counted based on the size of the pulse wave
Analysis using sheath flow impedance method: Under the sheath fluid wrapping, individual cells are arranged through the detector holes. As the cells are poor conductors relative to the electrolyte solution, pulse signals are generated when passing through. The number of pulse signals reflects the number of cells, and the strength of the pulse signal reflects the cell volume.
Perform statistical analysis on the frequency of cells of different sizes, using cell volume as the x-axis and cell quantity as the y-axis, to obtain an RBC/PLT histogram.
02
The detection principle of flow cytometry using semiconductor laser
In flow cytometry using semiconductor laser, analyze the forward scattered light (FSC), lateral scattered light (SSC), and lateral fluorescence (SFL) obtained by irradiating cells with a wavelength of 633nm laser, and count and classify the cells. Two types of scattered light (FSC, SSC) reflect cell size, surface structure, particle shape, nucleus shape, refractive index, and reflectivity. In general, the larger the cell, the stronger the signal of FSC, the more complex the internal structure of the cell, and the stronger the signal of SSC. In addition, lateral fluorescence mainly reflects the types and quantities of intracellular nucleic acids and organelles. For these three signals, manufacturers will use some innovative digital technologies and algorithms to classify and count white blood cells, nucleated red blood cells, reticulocytes, and platelets, while detecting abnormal and immature cells.
03
Principle of hemoglobin detection (SLS method)
Hemoglobin has a maximum peak at 535nm and a shoulder peak absorption curve at 560nm. Use a laser with a wavelength of 555nm inside the instrument to irradiate and measure its absorbance. The detection principle follows Lambert Beer's law
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