Hematology Analyzer
   HOME

TheInfoList



OR:

Hematology analyzers ( also spelled haematology analysers in
British English British English (BrE, en-GB, or BE) is, according to Lexico, Oxford Dictionaries, "English language, English as used in Great Britain, as distinct from that used elsewhere". More narrowly, it can refer specifically to the English language in ...
) are used to count and identify blood cells at high speed with accuracy. During the 1950s, laboratory technicians counted each individual blood cell underneath a
microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
. Tedious and inconsistent, this was replaced with the first, very basic hematology analyzer, engineered by
Wallace H. Coulter Wallace H. Coulter (February 17, 1913 – August 7, 1998) was an American electrical engineer, inventor, and businessman. The best known of his 85 patents is the Coulter principle, which provides a method for counting and sizing microscopic part ...
. The early hematology analyzers relied on Coulter's Principle (see
Coulter counter A Coulter counter is an apparatus for counting and sizing particles suspended in electrolytes. The Coulter counter is the commercial term for the technique known as resistive pulse sensing or electrical zone sensing, the apparatus is based on T ...
). However, they have evolved to encompass numerous techniques.


Uses

Hematology analyzers are used to conduct a complete blood count (CBC), which is usually the first test requested by physicians to determine a patients general health status. A complete blood count includes red blood cell (RBC), white blood cell (WBC), hemoglobin, and platelet counts, as well as hematocrit levels. Other analyses include: * RBC distribution width * Mean corpuscular volume * Mean corpuscular hemoglobin * Mean corpuscular hemoglobin concentrations * WBC differential count in percentage and absolute value * Platelet distribution width * Platelet mean volume * Large platelet cell ratio * Platelet criteria


Techniques

* Flow
Cytometry Cytometry is the measurement of number and characteristics of cells. Variables that can be measured by cytometric methods include cell size, cell count, cell morphology (shape and structure), cell cycle phase, DNA content, and the existence o ...
*
Spectrophotometry Spectrophotometry is a branch of electromagnetic spectroscopy concerned with the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. Spectrophotometry uses photometers, known as spec ...
* Electrical Impedance (Coulter's Principle) * Digital Microscopy with AI


Types


3-Part Differential Cell Counter

A 3-part differential cell counter uses Coulter's Principle to find the size and volume of the cell. The sample is lysed and dissolved into an electrolyte solution in a container, which also holds a smaller container. The smaller container has 2 pumps running to and from its solution, one creating a vacuum and the other replacing the lost solution. The smaller container has a small hole (an orifice) near the bottom of the container. Coulter's principle is applied through the use of two electrodes. One electrode (the internal electrode) is within the smaller container, and the other (the external electrode) is outside of the smaller container but within the electrolyte/sample solution. As the vacuum draws the sample cells through the orifice, the cell momentarily causes electrical resistance to the current as it passes through the orifice. This resistance is recorded, measured, amplified, and processed which can then be interpreted by the computer into a histogram. The 3-part analyzer is able to differentiate between 3 types of WBC's,
neutrophils Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in ...
,
lymphocytes A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adap ...
, and
monocytes Monocytes are a type of leukocyte or white blood cell. They are the largest type of leukocyte in blood and can differentiate into macrophages and conventional dendritic cells. As a part of the vertebrate innate immune system monocytes also infl ...
.


5-Part Differential Cell Counter

This type of hematology analyzer utilizes both Coulter's Principle and flow cytometry to determine the
granularity Granularity (also called graininess), the condition of existing in granules or grains, refers to the extent to which a material or system is composed of distinguishable pieces. It can either refer to the extent to which a larger entity is subd ...
, diameter, and inner complexity of the cells. Using hydrodynamic focusing, the cells are sent through an aperture one cell at a time. During this, a laser is directed at them, and the scattered light is measured at multiple angles. The absorbance is also recorded. The cell can be identified based on the intensity of the scattered light and the level of absorbance. A 5-part cell counter can differentiate all WBC types (neutrophils, lymphocytes,
basophils Basophils are a type of white blood cell. Basophils are the least common type of granulocyte, representing about 0.5% to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammator ...
,
eosinophils Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. A ...
, and monocytes). 5-part analyzers are more expensive than 3-part analyzers, but provide more in-depth information about the sample. Specific jobs, such as
allergy Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
testing, require 5-part differential analysis. However, most medical tasks can be completed with the 3-part analyzer.


References

{{Reflist Hematology Blood tests