Medonic CA530, Руководство пользователя

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Measuring Principles
26 03-11-24 1016en01
The PLT, RBC and WBC parameters are measured on a precise aliquot of the
sample. The amount of sample measured is determined by the volume of a pre-
cise glass column; called a metering tube. Two optical detectors are used to start
and stop detection.
The start detector is activated by the flow of the isotonic diluent through the me-
tering tube. As the meniscus passes the optical path it causes a voltage change that
activates the count and sizing circuitry of the system.
As the isotonic diluent continues to flow upward into the metering tube it passes
the stop detector. This action stops the count and analysing process and the pa-
rameters and distribution curves are displayed (and automatically printed if so
programmed by the user). Due to this principle, the CA instruments perform ab-
solute counts related to fixed volumes.
The instruments use a lower discriminator level at approx. 2.5 fl. All cells over this
level are analyzed and the counts are stored. The user defines, by means of setting
the discriminator level(s), which cell is seen as a PLT or as a RBC cell. A red blood
cell is defined as a cell with a volume larger than the upper PLT programmable
discriminator level.
1018.tif
electrical current
electrodes
Flow direction
cells
A
A=Aperture
1019.tif
glass tube
stop detector
fixed volume
start detector
flow