PN 177196BB
7-24
DATA MANAGEMENT AND REVIEW
DATA ANALYSIS REVIEW - RBC PARAMETERS
RBC Distribution Flags
1. Once an RBC distribution curve is developed, two positions on the distribution curve are
located, RBC1 and RBC2.
a. Thresholds RBC1 and RBC2 define the MICRO and MACRO regions and are
calculated based on standard deviation (SD) of the RBC population.
b. RBC1 threshold (monitoring area for microcytes) and RBC2 threshold (monitoring
area for macrocytes) identify the points on the curve that are ±2 SD from the mean.
2. When too many RBCs fall within the MICRO or MACRO regions, a flag is generated.
a. A MICRO flag is generated when the percentage of cells in the microcytic region
compared to the total number of RBCs exceeds the preset default limit of 5%.
b. A MACRO flag is generated when the percentage of cells in the macrocytic region
compared to the total number of RBCs exceeds the preset default limit of 7.5%.
Note: The MICRO and MACRO flags are independent of the Microcytosis and
Macrocytosis flags that are generated from the Low and High patient limits
3. The laboratory may establish its own limits to replace the preset default values..
Hgb Determination
1. The Hgb determination is made on the final 1:250 dilution in the DIL1/HGB bath.
a. The CBC lytic reagent in the dilution disrupts the RBCs to free the hemoglobin
which combines with the potassium cyanide to form a stable cyanmethemoglobin
compound.
b. The converted hemoglobin is directly measured through the optical part of the
DIL1/HGB bath using a spectrophotometric technique at a wavelength of 550 nm;
the photometric technique is based on Beer’s Law.
c. For each Hgb sample read value, the Analyzer takes three readings.
2. Transmittance of the sample dilution is compared with the transmittance of a reagent
blank.
a. The Hgb blank value measured during the first patient cycle after a Startup cycle is
stored as a reference blank; blank must be greater than 2.5 Vdc.
b. During each analysis cycle, the Analyzer checks the measured Hgb blank against the
stored Hgb blank reference value.
c. If the new Hgb blank reference value is within 3% of the old reference value, the
Hgb blank reference value is changed to this new value.
30 300
7616057
RBC1 RBC2
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