Difference between revisions of "Cell counter"
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A '''cell counter''' (typically automated) is a type of [[automated analyzer]] that samples the blood, and quantifies, classifies, and describes cell populations using both electrical and optical techniques. | A '''cell counter''' (typically automated) is a type of [[automated analyzer]] that samples the blood, and quantifies, classifies, and describes cell populations using both electrical and optical techniques. | ||
Electrical analysis involves passing a dilute solution of the blood through an aperture across which an electrical current is flowing. The passage of cells through the current changes the [[Electrical impedance|impedance]] between the terminals (the [[Coulter principle]]).<ref> | Electrical analysis involves passing a dilute solution of the blood through an aperture across which an electrical current is flowing. The passage of cells through the current changes the [[Electrical impedance|impedance]] between the terminals (the [[Coulter principle]]).<ref>{{cite web_short|title=The Coulter Principle|publisher=Beckman Coulter|url=https://www.beckmancoulter.com/wsrportal/wsr/industrial/particle-technologies/coulter-principle/index.htm|accessdate=23 September 2011}}</ref> A lytic reagent is added to the blood solution to selectively lyse the [[Red blood cell|red cells]] (RBCs), leaving only [[White blood cell|white cells]] (WBCs), and [[platelets]] intact. Then the solution is passed through a second detector. This allows the counts of RBCs, WBCs, and platelets to be obtained. The platelet count is easily separated from the WBC count by the smaller impedance spikes they produce in the detector due to their lower cell volumes. | ||
Optical detection may be utilised to gain a differential count of the populations of white cell types. A dilute suspension of cells is passed through a flow cell, which passes cells one at a time through a capillary tube past a [[laser]] beam. The reflectance, transmission and scattering of light from each cell is analyzed by sophisticated software giving a numerical representation of the likely overall distribution of cell populations. | Optical detection may be utilised to gain a differential count of the populations of white cell types. A dilute suspension of cells is passed through a flow cell, which passes cells one at a time through a capillary tube past a [[laser]] beam. The reflectance, transmission and scattering of light from each cell is analyzed by sophisticated software giving a numerical representation of the likely overall distribution of cell populations. | ||
[[Reticulocyte]] counts can now be performed by many analyzers, giving an alternative to time-consuming manual counts. Many automated reticulocyte counts, like their manual counterparts, employ the use of a supravital dye such as new methylene blue to stain the red cells containing [[Reticular fiber|reticulin]] prior to counting.<ref>http://www.biology-online.org/dictionary/New_methylene_blue</ref> Some analysers have a modular slide maker which is able to both produce a blood film of consistent quality and stain the film, which is then reviewed by a medical laboratory professional. | [[Reticulocyte]] counts can now be performed by many analyzers, giving an alternative to time-consuming manual counts. Many automated reticulocyte counts, like their manual counterparts, employ the use of a supravital dye such as new methylene blue to stain the red cells containing [[Reticular fiber|reticulin]] prior to counting.<ref>{{cite web_short|title=New methylene blue|publisher=Biology-Online.org|url=http://www.biology-online.org/dictionary/New_methylene_blue|accessdate=23 September 2011}}</ref> Some analysers have a modular slide maker which is able to both produce a blood film of consistent quality and stain the film, which is then reviewed by a medical laboratory professional. | ||
== References == | == References == | ||
Revision as of 18:51, 23 September 2011
A cell counter (typically automated) is a type of automated analyzer that samples the blood, and quantifies, classifies, and describes cell populations using both electrical and optical techniques. Electrical analysis involves passing a dilute solution of the blood through an aperture across which an electrical current is flowing. The passage of cells through the current changes the impedance between the terminals (the Coulter principle).[1] 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. This allows the counts of RBCs, WBCs, and platelets to be obtained. The platelet count is easily separated from the WBC count by the smaller impedance spikes they produce in the detector due to their lower cell volumes.
Optical detection may be utilised to gain a differential count of the populations of white cell types. A dilute suspension of cells is passed through a flow cell, which passes cells one at a time through a capillary tube past a laser beam. The reflectance, transmission and scattering of light from each cell is analyzed by sophisticated software giving a numerical representation of the likely overall distribution of cell populations.
Reticulocyte counts can now be performed by many analyzers, giving an alternative to time-consuming manual counts. Many automated reticulocyte counts, like their manual counterparts, employ the use of a supravital dye such as new methylene blue to stain the red cells containing reticulin prior to counting.[2] Some analysers have a modular slide maker which is able to both produce a blood film of consistent quality and stain the film, which is then reviewed by a medical laboratory professional.
