CELL-DYN
®
3200 System Operator’s Manual
3-15
9140181H—October 2001
Section 3
Principles of Operation
Finally, the instrument evaluates the area below the lymphocyte cluster but above
the hardware threshold (channel 23). Any particles that fall in this area are
separated from the lymphocytes by a dynamic threshold. The following cell types
may be present in this region:
NRBCs
Unlysed RBCs
Giant PLTs
PLT clumps
All particles in this region are excluded from the WBC count and the Differential.
Other Scatterplots
90°/0°
The scatter information is plotted with the 90° scatter on the Y axis and the 0°
scatter on the X axis.
90°D/0°
The scatter information is plotted with the 90°D scatter on the Y axis and the 0°
scatter on the X axis.
90°D/10°
The scatter information is plotted with the 90°D scatter on the Y axis and the 10°
scatter on the X axis.
All scatterplots may be displayed and printed at operator request.
Nuclear Optical Count
Samples containing fragile WBCs are difficult to measure accurately because of
the rapid breakdown of cells during the measurement process. To obtain an
accurate WBC count, an alternate method using the HGB segment (instead of the
WBC segment) is used to measure samples containing fragile WBCs.
The HGB sample segment, after being measured in the HGB Flow Cell, is
transferred to the Optical Flow Cell instead of being sent to a waste chamber as in
normal Patient cycles. While in the HGB Flow Cell, the HGB reagent lyses the
cytoplasmic membrane of the white blood cells but allows the nuclear membrane
to remain intact. This results is a greater stability of the white cells in the sample.
The HGB segment is lysed for approximately 15 seconds before it is sent to the
Optical Flow Cell.
As the HGB segment passes through the Optical Flow Cell, the nuclei of the cells
are counted. The results of this measurement are stored in the Data Log as NOC.