Westgard Flashcards
What are the westgard rules
A system of rules that define specific performance limits for a particular assay to detect systemic and random errors
How to interpret westguard rules
First number indicates # of data points
Second number for how many stdevs
What is a 1(2)s
1 point outside of 2 SD
Warning
When do you reject a run in respect to westgaurd rules
When one point is outside 2 SD
1(3)s
1 point outside of 3 SD
2(2)s
Two consecutive points outside of 2 SD on same side
R(4)s
Range of two points greater than 4SD
4(1)s
Four consecutive points exceed 1SD on the same side of the mean
10x
10 consecutive points are above or below mean
What should you do when a run is rejected
Search for recent events and prepare new controls
What is calibration
Refers to the act of evaluating and adjusting the precision and accuracy of measurement equipment
Intended to eliminate or reduce his in instrument readings
When to calibrate
Before major critical measurements or after an event
QC problem: drift (trend)
what actions are taken
Check outdated on materials
Calibrate assay
If not solved then replace reagent and calibrate again
QC problem: shift
Determine when shift took place and events on that date
Calibrate new reagent and fresh calibrator
Continual shift = instrument malfunction
QC problem: random error
Repeat control, if repeat is out calibrate
If multiple QC are out then QC problem
