Abbott CELL-DYN 3200 System Operator's Manual page 99

Section 3
CELL-DYN ® 3200 System Operator's Manual
9140181H—October 2001
Fragile WBCs and Resistant RBCs
When running samples in the normal Patient mode, the operator may suspect the
presence of fragile WBCs when the FWBC flag is displayed or may suspect the
presence of resistant RBCs when the RRBC and NRBC flags are displayed.
In the case of samples containing fragile WBCs or resistant RBCs, an alternate
method is used to measure white blood cells. The results of this method are referred
to as the Nuclear Optical Count (NOC). The NOC measurement is derived from the
HGB dilution as described below. Refer to Nuclear Optical Count and Resistant
RBC later in this section for additional information.
There are two different key labels on the SPECIMEN TYPE screen, one for fragile
WBCs and one for resistant RBCs. Refer to Run Menu Soft Keys, Subsection:
Specimen Type in Section 5: Operating Instructions for a discussion of the
Specimen Types available.
When the Fragile WBC specimen type is selected, both NOC and WOC are
reported in the Data Log. The NOC value is reported as WBC on the RUN screen
and Laboratory Worksheet.
When the Resistant RBC specimen type is selected, both NOC and WOC are
reported in the Data Log. Either NOC or WOC is reported as WBC (based on
algorithmic decision-making) on the RUN screen and Laboratory Worksheet.
NOTE: When QC specimen type is selected, both NOC and WOC are reported in
the Data Log. Either NOC or WOC is reported as WBC (based on
algorithmic decision-making) on the RUN screen.
The analysis for Fragile WBC and Resistant RBC is performed as follows:
1. After the HGB sample is measured (refer to Hemoglobin Analysis earlier in
this section), the Sample Transfer Pump transfers the diluted solution from
the HGB Flow Cell to the Optical Flow Cell Sample Feed Nozzle.
2. Diluent/Sheath reagent, under constant pressure in the Sheath Reservoir, is
directed into the Optical Flow Cell.
3. Sequentially, the Sample Metering Syringe injects 140 µL of the HGB
dilution into the flow cell.
4. The higher speed of the sheath which surrounds the HGB dilution, and the
special geometry of the flow cell, focus the HGB dilution stream so that
individual cells can be counted.
5. A laser beam is focused on the flow cell. As the sample stream intersects the
laser beam, the light scattered by the cells is measured by the 0 degree
detector. The nuclei of the lysed cells are counted as the NOC result.
6. The WBC Analysis in Fragile WBC and QC specimen type occurs as
described in WBC Analysis earlier in this section.
7. The WBC Analysis in Resistant RBC mode occurs as described in WBC
Analysis above except that the diluted WBC segment is lysed in the WBC
Mixing Chamber for an additional 15 seconds.
Principles of Operation
3-5