What does impedance measurement in hematology detect?

Impedance measurement in hematology is a technique that detects changes in electrical current between two electrodes as cells pass through an electrical field. When cells pass through this field, they cause fluctuations in the impedance, or resistance, of the electric current. The degree of these fluctuations directly correlates with various parameters of the cells, such as size and volume. Harshly speaking, the principle relies on the fact that cells are non-conductive when compared to the surrounding fluid, and as they intersect the electrodes, they displace fluid and alter the flow of electrical current.

This method is widely utilized in automated hematology analyzers to provide important information about blood cell counts and characteristics, distinguishing between different cell types based on their size and number. Therefore, the choice indicating that impedance measurement detects changes in electrical current between two electrodes accurately reflects the fundamental principle of how this technique operates in the analysis of blood samples.