Instrument Operating Manual
CyFlow® Cube 8 Rev-27_2015-07-02
Sysmex Partec GmbH
Am Flugplatz 13, 02828 Görlitz, Germany · Phone +49 3581 8746-0 · Fax +49 3581 8746-70 · [email protected] ·
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2.2 In flow cytometry, what is...
… a parameter?
In flow cytometry, parameter denotes a measured property of
the particles. Frequently, a parameter is synonymous to an
optical channel. E.g. an instrument with 6 parameters is
equipped with 6 optical detectors.
… a one-parameter histogram?
A one- parameter histogram displays the distribution of cells
among a specific property, e.g. how many cells contain a given
quantity of DNA or bind a given number of antibody molecules.
… a histogram channel?
The measured signal intensity is assigned to one of 65536 (16bit) quantity classes or
channels. In a one-parameter histogram the channels are represented on the x-axis.
… the count in a histogram?
The number of cells being assigned to a given channel is referred to as channel content
or simply count. In a one-parameter histogram, the count is shown on the y-axis.
… a peak?
All cells having about equal characteristics among the analysed cell property (e.g. content
of a specific constituent like DNA) form a peak. In the case of a typical DNA histogram
one peak represents the G1 and another peak (with twice the channel value) represents
the G2/M phase of the cell cycle.
In case of immunolabelled cells often one peak for unlabelled (negative) and one peak for
labelled (positive) cells can be detected. Peaks can be analysed by identifying them with
region markers.
… background in a histogram?
Histograms sometimes show undesired signals in the lower channels, frequently called
´noise´ or ´background´. These signals may originate from cell fragments or other
