PN 177196BB
7-22
DATA MANAGEMENT AND REVIEW
DATA ANALYSIS REVIEW - RBC PARAMETERS
b. If the two counts differ by more than a predefined limit:
1) RBC result is flagged with a voteout V-flag.
2) MCV, MCH, MCHC, and RDW parameters are replaced with (
. . . .) code.
3. Since WBCs fall in the red blood cell size range, they are counted and sized as RBCs
when this 1:10,000 dilution is analyzed.
Note: The WBCs are not gated out of the count because any interference is usually
insignificant; there are normally very few WBCs (thousands) in comparison to the
number of RBCs (millions). Only when the white count is markedly elevated is the red
cell count or histogram influenced.
Hematocrit Measurement
1. The Hematocrit measurement is obtained from the RBC/PLT dilution in the RBC bath.
a. The height of the pulse generated by the passage of a cell through the aperture is
directly proportional to the volume of the analyzed RBC.
b. The hematocrit (Hct) is the sum of all the digitized pulses.
2. To obtain a hematocrit measurement, the Analyzer compares and votes on data collected
for two 6-second count periods.
a. If the two values agree, the Hct result is reported.
Hct = Sum of digitized pulses x calibration factor
Hct displayed and printed as a percentage (%)
b. If the two values differ by more than a predefined limit:
1) Hct result is flagged with a voteout V-flag.
2) MCV and MCHC parameters are replaced with (
. . . .
) code.
RBC Histogram
1. In addition to being counted, RBCs are categorized according to size (from 30 fL to
300 fL) by a 256-channel pulse-height analyzer.
a. Pulse-height analyzer uses a number of thresholds to sort the particles into several
size (volume) categories and to develop a size distribution curve of the particles.
b. Raw data for developing the RBC histogram is collected through two consecutive
time periods of 6-seconds each (for a total of 12 seconds).
2. The RBC distribution curve reflects the native size of the red blood cells and any other
particle in red blood cell size range.
a. The RBC histogram provides the information for determining a helpful descriptor of
the red cell population, RDW (Red cell Distribution Width).
b. The RBC histogram is also used to determine if a red blood cell population is
typical; if not, descriptive flagging is generated.
To Next Page
Loading...
