mlt 210 - automated blood cell analysis

electronic impedance

method that helps us count the number of cells

electricity passes through a hole while sample fluid also flows through the hole. as cells pass through, the current is interrupted and by counting these we can determine the number of cells

sources of error in electronic impedance

protein buildup, carryover from other samples, coincident passage loss, recirculation of cells

radiofrequency

RF resistance is used with direct current impedance

the change in the electromagnetic current as the cell moves through the aperture is relative to the cells density (AKA tells us what’s inside the cell)

optical scatter

flow cytometry

cells pass individually through a light source, usually a light source. as a cell passes through, light is scattered in all directions (absorption, diffraction, refraction, reflection)

forward angle light scatter (0 degrees)

type of optical scatter measurement

cell volume due to diffraction

orthogonal light (side) scatter (90 degrees)

type of optical scatter measurement

degree of cellular internal complexity due to reflection and refraction of structures inside the cell

RDW

uses frequency distribution chart created when red cells are counted and measured

expresses the amount of variation in red cell size

high levels indicate a greater amount of anisocytosis

RDW-CV

coefficient of variation

reference range is 11.5% - 14.5%

retic count

most recently automated

gives idea of bone marrow function

WDF channel

red cells are lysed

white cell membranes are perforated, and fluorescent dyes are attached to the DNA and RNA

plots side scatter vs. side fluorescence