A13914AF
5-2
Quality Control
Quality Control
Each time a control result is received, the Z-score is calculated. If the Z-score is less than ± 2 SD, the
result is within the assigned control range (the assigned mean ± 2 assigned standard deviations) and
is considered acceptable.
NOTE
Results are flagged at time of run. Flagging is not changed if the operator modifies the assigned mean
and/or SD.
Accuracy and Precision Flags
The DxC uses the following Westgard rules for evaluation of QC data.
•
1-2S: Result Between ± 2SD and ± 3SD From the Assigned Mean
If the result is between ± 2 and ± 3 standard deviations from the assigned mean, the result:
—
is flagged as > 2SD on the QC Log report.
—
appears in yellow on the QC LOG and QC CHART screens.
—
is highlighted in a pop-up note on the monitor as the system is running.
•
1-3SD: Result Greater Than 3SD From the Assigned Mean
If the result is greater than ± 3 SD from the assigned mean, the result:
—
is flagged as > 3SD on the QC Log report.
—
appears in red on the QC LOG and QC CHART screens.
—
is included in a real-time pop-up window as the system is running.
•
2-2S and R-4S: Results Between 2 SD and 3 SD as Compared to the Previous Result
In addition, the Z-score for the current result is compared with the Z-score of the previous
result in the same QC file. If both Z-scores are beyond 2 SD on the same side of the assigned
mean, the current result receives an "Accuracy" flag on the QC Log report; this flag signifies a
violation of the 2-2S rule. These values appear red in the QC log and QC chart.
If the two results being compared are greater than 2 SD on opposite sides of the assigned mean,
the current result receives the "Precision" flag on the QC Log report, signifying a violation of
R-4S rule. These values appear red in the QC log and QC chart.
•
Results Greater Than 4 SD From the Assigned Mean
Results greater than 4 SD are included in the QC Log and QC Chart, but are not used to calculate
statistics.
E014425L.EPS
Z =
X = the individ
u
al control res
u
lt
X = the assigned mean for the control
SD = the assigned standard deviation for the control
SD
X - X
Содержание UniCel DxC 600
Страница 4: ...A13914AF iv Revision History ...
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Страница 36: ...A13914AF xxxvi Introduction How to Use this Manual ...
Страница 68: ...A13914AF 1 32 System Description Main Screen and Program Structure Figure 1 20 Program Structure QC Setup ...
Страница 71: ...A13914AF 1 35 System Description Main Screen and Program Structure 1 Figure 1 23 Program Structure Utils ...
Страница 132: ...A13914AF 3 34 System Setup Options Auto Generation of Control ...
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