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2 English Referencehematology *** yzer<
3 OverviewHematology analyzer is one of the most widely used instruments in hospital clinical testing, mainly used for testing blood samples, which can qualitatively and quantitatively analyze the formed components of blood and provide relevant information. With the rapid development of computer technology in recent years, the technology of blood cell analysis has also shifted from trichotomous to pentachotomous, and from two-dimensional space to three-dimensional space, and we also notice that many of the five-classification techniques of modern blood cell analyzers have adopted the same technology as that of today's very advanced flow cytometers, such as scattered-light detection technology, sheath-flow technology, and laser technology, etc. In this paper, we focus on the five-classification techniques of modern blood cell analyzers. In this paper, we focus on the detection methods of the five-classification blood cell analyzer and its application.
4 Electrical impedance, high-frequency conductivity and laser scattering joint detection methodThis is a new technology introduced by Coutler in 1987, the blood cells suspended in the electrolyte, with a certain current through the sensor inside and outside the two electrodes, due to the electrical impedance of the blood cells is very large, when the blood cells through the two electrodes, the impedance between the electrodes instantly increased, the formation of amplitude and the volume of the blood cells is proportional to the formation of the electrical pulse, the size of the pulse can be measured according to the cell. According to the size of the pulse, the volume of the cell can be measured. In the measurement of red blood cells, the use of a pulse screener, the amplitude of the smaller platelet pulse removed, retaining the red blood cells and leukocytes pulse, because the number of leukocytes in the blood is less than the number of red blood cells 1/500, so the total data is approximated as a red blood cell count. In measuring leukocytes, hemolysin is utilized to dissolve the red blood cells, and then the remaining leukocytes are counted. For platelet counts, the threshold of the pulse screener is lowered, the total number is counted, and the count of red blood cells (which includes the count of white blood cells) is subtracted from the platelet count. Since different types of cells with the same volume produce the same pulse amplitude, it is not possible to completely distinguish them by volume alone, and the use of high-frequency conductivity and laser scattering to analyze the internal structure of leukocytes can make up for this defect. Although the cell wall can not make the low-frequency current through, but can pass the high-frequency current, the cell nuclei of different sizes and densities, their impedance to high-frequency current is also different, so it can be used to distinguish between leukocytes. The laser scattering technique is mainly used to examine the surface characteristics and internal structure of cell membranes. Laser scattering on the structure of cell particles and the density of the ability to distinguish between coarse particles produced by light scattering than fine particles, which can be used to distinguish between granulocytes, the United States COULTER STKS, MAXM series of hematology analyzers five classified by the use of electrical resistance, high-frequency conductivity and laser scattering joint detection method.
5 Light Scattering and Cytochemical Staining Combined Detection Method
It uses laser scattering and peroxidase staining technology for cell classification. Eosinophils have strong catalase activity, neutrophil plasma is rich in catalase, followed by monocytes, and primitive cells, while lymphocytes and basophils are deficient in this enzyme. The enzyme is immobilized in the leukocyte plasma by using microscopic amounts of blood diluted with a hypertonic liquid containing detergent and formaldehyde and incubated for several tens of seconds, at which time the cells are destroyed by the detergent and the enzyme is immobilized in the leukocyte plasma, and then continued with a second reaction by adding hydrogen peroxide and tetralin to heat it, at which time the catalase enzyme in the cells to be tested breaks down the hydrogen peroxide and produces oxygen, which causes tetralin to develop its own color and precipitate and localize in enzyme-containing particles. Such cells are classified by the laser beam due to light scattering and different cell sizes. Obviously, basophils, lymphocytes, and primitive cells cannot be detected because they do not contain this enzyme. Therefore, some instruments are equipped with a special basophil detection system, which uses a time-difference method for the measurement channel, and the same channel as the RBC/PLT measurement system***. Due to the action of the reagent, all cells in the blood are lysed except for the basophils. The amount of bare nuclei of basophils along with other cells produces a cellular distribution map. Intact basophils scatter at a high narrow angle and are localized in the upper half of the diagram, with naked nuclei in the lower half, and different naked nuclei are distributed differently on the x-axis because of their different structures. Individual nuclei are located on the left, and the more lobulated the more to the right. The computer analyzes the ratio of foliated nuclei to the angular scattering peaks of individual nuclei, and the ratio is the result reported by the analyzer.
The TECHNICON H-Series analyzers use this technology.
6 Electrical Impedance and RF Conductivity Combined DetectionThis method uses four separate detection systems to detect different types of cells ① Lymphocyte, monocyte, and neutrophil detection system: the addition of hemolytic agents to the cell suspension Huai to make erythrocyte lysis, while the leukocytes to remain intact, cytoplasmic and nuclear morphology approximates physiological state, when these cells pass through the detection system, leukocytes to the When these cells pass through the detection system, the leukocytes are subjected to a combination of electrical resistance (measuring cell volume) and radiofrequency conductivity (detecting cell nuclei and particle density), which results in the separation of the cells into three groups: lymphocytes, monocytes and neutrophils. ② Eosinophils and Basic Cells Detection System: A special hemolytic agent is added to the cell suspension, and all cells except eosinophils and basic cells are lysed or shrunk, and then eosinophils or basic cells that remain intact are counted. ③Na?ve Cell Detection System: Sulfated amino acids are added to the cell suspension, due to the different occupancy, the amino acids bound to the na?ve cells are more than the mature cells and resistant to hemolytic agents, when hemolytic agents are added, the mature cells are lysed, and only the na?ve cells that may be present are retained and used for counting.
At present, the NE1500 of Japan's Tohya company, SYSNEX's SE9000 blood cell analyzer is to use this method for the five subgroups.
7 Multi-angle Laser Polarized Light Scattering DetectionInstruments using this technique use a sheath flow Huai to dilute the specimen blood, the internal structure of diluted leukocytes is similar to the natural state, only the alkaliphilic cells due to their hygroscopic properties of the cellular structure of the cell has a slight change. The hemoglobin within the red blood cells is separated from the cells by the high osmotic pressure. While water from the sheath flow enters into the erythrocyte so that the cell membrane structure remains intact, it has the same refractive coefficient as that of the sheath flow and does not affect the detection of white blood cells. The instrument simultaneously detects the scattered light from the cells passing through the laser beam from four angles: 0° front-angle light scattering to determine cell volume, 10° narrow-angle light scattering to determine cell structure, 90° vertical light scattering to measure intracellular particles and cytoplasm, and 90° defocused light scattering to separate eosinophils from neutrophils and other cells.ABBOTT's CD3000 and CD3500 blood cell analyzers.