Automated cell-counting instruments

Automated Cell Counter Instrument that uses electric impedance or optical light scatter to rapidly count blood cells. 

Automated Cell-Coimting Instruments. Until the mid-1950 s, cell counts were performed manually using a diluted fluid and a hemocytometer, and blood smears were viewed microscopically. Modern automated instruments can perform a complete blood count (CBC), which includes red blood cells, white blood cells, platelets, hemoglobin, hematocrit, and a five-part differential. This testing accounts for... 

The first commercially successful automated blood cell counter, the Model A Coulter Counter, was introduced in 1956. The Model A counted cells by using electrical impedance properties, and the Coulter Counter quickly became the instrument of choice for counting red and white blood cells. When it was later demonstrated that cell volume was roughly proportional to the electrical impedance signal amplitude, the Coulter Counter was modified to provide MCV as the mean of the individually measured red cell volumes. Impedance counters calculated HCT as (RBC x MCV)/10 and, by the early 1970s, these instruments also counted platelets. By the mid-1970s, impedance counters combined with photometric hemoglobinometers to produce CBCs. 

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