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Celloscope automated cell counter was developed in the 1950s for enumeration of erythrocytes, leukocytes, and thrombocytes in blood samples. [1] Together with the Coulter counter, the Celloscope analyzer can be considered one of the predecessors of today's automated hematology analyzers, as the principle of the electrical impedance method is still utilized in cell counters installed in ...
Hematology analyzers (also spelled haematology analysers in British English) are used to count and identify blood cells at high speed with accuracy. [ 1 ] [ 2 ] [ 3 ] During the 1950s, laboratory technicians counted each individual blood cell underneath a microscope .
The major disadvantages of the flow cell format are that it is much more expensive to manufacture and is typically fixed to a single channel width, whereas the aperture format offers a wide variety of aperture sizes. Microfluidic approaches have been used to apply the Coulter principle to lab-on-a-chip particle detection. These techniques allow ...
The passage of cells through the current changes the impedance between the terminals (the Coulter principle). [6] A lytic reagent is added to the blood solution to selectively lyse the red cells (RBCs), leaving only white cells (WBCs), and platelets intact. Then the solution is passed through a second detector.
Blood is sampled and diluted, and moves through a tube thin enough that cells pass by one at a time. Characteristics about the cell are measured using lasers (fluorescence flow cytometry) or electrical impedance. Because not everything about the cells can be measured at the same time, blood is separated into a number of different channels.
The Coulter principle uses electrical impedance measurements to count blood cells and determine their sizes; it is a technology that remains in use in many automated analyzers. Further research in the 1970s involved the use of optical measurements to count and identify cells, which enabled the automation of the white blood cell differential.
The first impedance-based flow cytometry device, using the Coulter principle, was disclosed in U.S. Patent 2,656,508, issued in 1953, to Wallace H. Coulter.Mack Fulwyler was the inventor of the forerunner to today's flow cytometers – particularly the cell sorter. [6]
In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. [1]Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. [2]