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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 .
As electric current detectors became more sensitive and less expensive, the Coulter counter became a common hospital laboratory instrument for quick and accurate analysis of complete blood counts (CBC). The CBC is used to determine the number or proportion of white and red blood cells in the body.
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 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.
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]
Often, data obtained by electrochemical impedance spectroscopy (EIS) is expressed graphically in a Bode plot or a Nyquist plot. Impedance is the opposition to the flow of alternating current (AC) in a complex system. A passive complex electrical system comprises both energy dissipater and energy storage elements.