Abbott CELL-DYN 3000 Operator's Manual - Wbc Measurement
CELL-DYN
3000 System Operator’s Manual
3-5
9140240E — May 1995
Chapter 3 Principles of Operation
WBC Measurement
Overview
This section gives an overview of the WBC measurement. The details are
discussed in the sections covering the
The optical channel is used for the determination of WBC data. A 1:51
dilution of the sample is made with the Sheath reagent. The WBC
metering syringe injects a metered volume of this dilution into the sheath
stream. The sample stream is then hydrodynamically focused to align the
cells in single file as they pass through the WBC flow cell, which is an
optically clear quartz chamber. A vertically polarized helium neon laser
is the light source.
The instrument measures the traditional forward angle light scatter (1—
3
°
, referred to as 0
°
) and orthogonal light scatter
(70—110
°
, referred to as 90
°
) parameters. Two additional scatters,
narrow-angle light scatter (7—11
°
, referred to as 10
°
) and
ninety-degree depolarized scatter (70—110
°
, referred to as 90
°
D), are
measured. This is referred to as MAPSS™ (for multi-angle polarized
scatter separation) technology. Various combinations of these four
measurements are used to classify the WBC subpopulations and provide
morphological flagging.
The WBC count is determined by enumerating the number of
occurrences above the computer-generated threshold in the 0
°
channel.
The information from all four measurements is used to differentiate the
WBCs into five subpopulations:
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
The WBC data is presented graphically as scatterplots. It may also be
presented in two histograms at operator request.
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