Hematology 1 - Laboratory Past Paper PDF 2024-2025

CENTRO ESCOLAR UNIVERSITY - MANILA I PRML141L HEMATOLOGY 1 - LABORATORY 3RD YEAR A.Y 2024 - 2025 I 1ST SEMESTER MGLAGO ADAPTED FROM: LECTURE/POWERPOINT HANDOUT ON AUTOMATION...

CENTRO ESCOLAR UNIVERSITY - MANILA I PRML141L HEMATOLOGY 1 - LABORATORY 3RD YEAR A.Y 2024 - 2025 I 1ST SEMESTER MGLAGO ADAPTED FROM: LECTURE/POWERPOINT HANDOUT ON AUTOMATION 2. RADIOFREQUENCY In this newer application, high-voltage electromagnetic GENERAL PRINCIPLES OF AUTOMATED BLOOD CELL current is used to detect cell size, based on the cellular ANALYSIS density. 1. ELECTRICAL IMPEDANCE (Resistance) The radiofrequency (RF) pulse is directly proportional to the nuclear size and density of a cell. RF or conductivity is related Electronic impedance, or low-voltage direct current (DC) to the nuclear-cytoplasmic ratio, nuclear density, and resistance, was developed by Coulter in the 1950s, and is the cytoplasmic granulation. most common methodology used. PRINCIPLE: Cell counting and sizing are based on the 3. OPTICAL DETECTION detection and measurement of changes in electrical impedance (resistance) produced by a particle as it passes In the optical or hydrodynamic focusing method of cell through a small aperture. counting and cell sizing, laser light is used. A diluted blood As a dilute suspension of cells is drawn through the aperture, specimen passes in a steady stream through which a beam of the passage of each individual cell momentarily increases the laser light is focused. As each cell passes through the sensing impedance (resistance) of the electrical path between two zone of the flow cell, it scatters the focused light. submerged electrodes that are located on each side of the Scattered light is detected by a photodetector and converted aperture. into an electrical pulse. The number of pulses generated is On the Oscilloscope screen: The number of pulses directly proportional to the number of cells passing through the generated during a specific period is proportional to the sensing zone in a specific period. number of particles or cells. The amplitude (magnitude or The application of light scatter means that as a single cell height of the voltage pulse) of the electrical pulse produced passes across a laser light beam, the light will be reflected indicates the cell’s volume. and scattered. The patterns of scatter are measured at The output histogram is a display of the distribution of cell various angles (forward scatter 180 degrees and right angle volume and frequency. Each pulse on the x-axis represents 90 degrees). size in femtoliters (fL); the y-axis represents the relative Scattered light provides information about cell structure, number of cells shape, and reflectivity. These characteristics can be used to differentiate the various types of white blood cells (WBCs) and to produce scatter plots with a five-part differential. CHARACTERISTICS OF A LIGHT SCATTER OPTICAL LIGHT SCATTER ○ In this category, light amplification is generated by stimulated emission of radiation. Three independent processes are operational. These are as follows: 1. Diffraction and the bending of light around corners with the use of small angles 2. Refraction and the bending of light because of a change in speed with the use of intermediate angles 3. Reflection and light rays turned back by the surface or an obstruction with the use of large angles ANGLES OF LIGHT SCATTER ○ Various angles of light scatter can aid in cellular analysis. These are as follows: 1. Forward light scatter 0 degrees. This is diffracted light, which relates to the volume of the cell. 2. Forward low-angle light scatter 2 to 3 degrees. This characteristic can relate to size or volume. 3. Forward high angle 5 to 15 degrees. This type of measurement allows for description of the refractive index of cellular components. 4. Orthogonal light scatter 90 degrees. The result of this application of light scatter is the production of data based on reflection and refraction of internal components, which correlates with internal complexity. DIONES 1  CONDITIONS THAT CAUSE INTERFERNCES ON MOST HEMATOLOGY ANALYZERS Rodak’s Hematology, Chapter 15: Automated Blood Cell Analysis, Page 226 2