3-18 CELL-DYN 3000 System Operator’s Manual
9140240E — May 1995
Principles of Operation Chapter 3
RER
The RER (red cell editing ratio) is a process of pulse editing that is
applied to the RBC pulses before the MCV is derived. The instrument
compensates for the aberrant pulses produced by the non-axial passage
of the RBCs through the aperture. These pulses are included in the RBC
count but eliminated from the RBC sizing determination.
Volumetric Metering
An absolute cell count cannot be obtained unless the precise volume of
diluted whole blood that passes through the aperture during the count
cycle is known.
1
The CELL-DYN 3000 utilizes the volumetric metering
process to regulate the count cycle and ensure that a precise volume of
sample is used for the RBC/PLT measurement.
The RBC/PLT metering assembly contains a precision-bore glass tube
fitted with two optical detectors. (See Figure 3.9.) The distance between
the detectors is set to precisely measure 100 µL. Hemoglobin Lyse is
added to the metering tube to create a meniscus. When the RBC/PLT
cycle is initiated, the liquid flows down the metering tube.
Figure 3.9: Volumetric Metering
Meniscus
Upper Detector
(count initiated)
Lower Detector
(count completed)
Count
Volume
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