What is the role of electrical impedance in hematology analyzers?

Electrical impedance plays a crucial role in hematology analyzers by measuring the resistance encountered as cells pass through an electrical field. When the cells traverse this field, they disrupt the flow of voltage, leading to changes in electrical resistance or impedance. These changes are directly related to the size of the cells. As larger cells cause greater changes in impedance than smaller cells, this method allows the analyzer to efficiently count and differentiate cells based on their size.

This technique is particularly effective in providing rapid and reliable counts of various blood cell types, such as red blood cells, white blood cells, and platelets. Each of these cell types has a characteristic size range, allowing for proper identification and enumeration when analyzed with electrical impedance.

Other methods mentioned, such as measuring light absorbance or assessing hemoglobin concentration, utilize different principles and are not directly linked to the size differentiation process that electrical impedance provides. These alternatives focus on different aspects of cell assessment, like analyzing specific content or features rather than counting cells based on their physical dimensions.