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The Coulter principle states that particles pulled through an orifice, concurrent with an electric current, produce a change in impedance proportional to the volume of the particle traversing the orifice. This pulse in impedance originates from the displacement of electrolyte caused by the particle.
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 ...
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.
Hematology analyzers are used to conduct a complete blood count (CBC), which is usually the first test requested by physicians to determine a patient's general health status. [5] A complete blood count includes red blood cell (RBC), white blood cell (WBC), hemoglobin, and platelet counts, as well as hematocrit levels.
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.
It is based on the fact that cells show great electrical resistance; in other words, they conduct almost no electricity. In a Coulter counter the cells, swimming in a solution that conducts electricity, are sucked one by one into a tiny gap. Flanking the gap are two electrodes that conduct electricity. When no cell is in the gap, electricity ...
Joseph and Wallace Coulter circumnavigates these difficulties by inventing the principle of using electrical impedance to count and size microscopic particles suspended in a fluid. [5] [13] This principle is today known as the Coulter principle and was used in the automated blood cell counter released by Coulter Electronics in 1954.
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 particles suspended in fluid.