Beckman Coulter UniCel DxC 600, Instructions For Use Manual

Page: 162 / 498

A13914AF
4-30
Reagent Load/Calibration
Slope Offset Adjustment
Slope Offset Recommendations
When slope and offset modification is desired, the slope and offset values to be used must be
experimentally derived from statistically significant patient correlation studies. It is recommended
that patient samples are run over a period of several days by both methods, using controls to
monitor accuracy. A good range of data should be achieved by analyzing below normal, normal, and
above normal samples. Patient sample data (only) should be used for linear regression analysis with
Synchron values as
y
values and other method values as
x
values. A minimum of 40 patient samples
is recommended. From this analysis, the regression equation in the following form is obtained:
To obtain the desired slope and offset values for entry into the
Slope/Offset Adjustment
screen, the
equation above must be rearranged as follows:
The Synchron values need to be multiplied by the slope value and then the offset value is added:
Reported sample result = Synchron calculated sample result × (slope) + offset.
1
Select
Rgts/Cal
from the menu bar.
2
Select
Cal Options F6
.
3
Select
Slope/Offset adjustment
from the pull-down menu.
y = mx+b
where:
y = Synchron value
x = other method value
m = slope of regression line
b = y-intercept of regression line (offset)
x = (y - b) / m
x = (y × 1 / m) + (-b / m)
Slope = 1 / m
(value to be entered)
Offset = -b / m
(value to be entered)