SYSMEX XE-5000 - Page 113

CHAPTER 7 Quality control
Sysmex XE-5000 Instructions for Use 7-17
Revised April 2007
Variable target
The variable target function serves to calculate a control
target value automatically from the data stored in the control
file. The variable target function operates in both X
/L-J control
and X
M when the target value is set as space.
The variable target value calculated by this function does not
appear in the Set Target/Limit dialog box. It appears only in
the Target column of the QC charts.
How target values are calculated
The target value calculation operation is explained in an
example using an empty file (file with no control data) as
follows:
In this example, the parameter selected is RBC, the target is
set at 0 and the limit (%) is set at 2.3%. The limits above and
below this target are calculated from the following equation.
(The limit values thus obtained are rounded up. UL = upper
limit, LL = lower limit.)
Range (UL and LL) = Target X Limit(%) / 100
1. 4.5 million is input as the first RBC control data. The
variable target will be set at 4.50, and the QC Chart will
show the values in the figure on the right.
2. 4.45 million is input as the second RBC control data. The
variable target remains the same, because the
denominator (N-1) in the equation X/N-1 is 1 in this
instance.
3. 4.52 million is input as the third RBC control data. The
variable target changes to 4.48 (= (4.50 + 4.45) / 2).
4. 4.21 million is input as the fourth RBC control data. The
variable target, calculated using all three of the previous
control data, changes to 4.49 (= (4.50 + 4.45 + 4.52) / 3).
The variable target function is useful for setting control target
values when the instrument is monitored using control blood
(the analyzed values for which, unlike calibrator, are not
reliable in an absolute sense).
UL
RBC
LL
4.61
4.50
4.39
N=1, UL-TARGET=0.11
UL
RBC
LL
4.61
4.50
4.39
N=2, UL-TARGET=0.11
UL
RBC
LL
4.59
4.48
4.37
N=3, UL-TARGET=0.11
UL
RBC
LL
4.60
4.49
4.38
N=4, UL-TARGET=0.11