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Welcome to Bio-Rad's Blackboard Training. This is a series of short, informal tutorials
brought to you by industry experts.
Today we'll discuss establishing QC targets and ranges.
It is important for labs to establish targets.
There are a number of ways to do this. Meet John.
He uses an assayed control material.
This means that the manufacturer has provided initial targets and ranges.
John uses these to assess his QC data.
A better approach would be for John to use his own data to calculate his QC targets and
ranges.
This would allow him to take into consideration recalibration, reagent and calibrator lot
changes, maintenance cycles, and environmental factors.
Let's look at a possible process for establishing QC ranges and target values.
First, you should calculate the mean and SD.
Calculating the mean is pretty easy. Check out our video on the mean if you need more
information.
You should have at least 20 points. These should be gathered over a period of 20 days.
20 days allows for vial to vial variation as well as open bottle and analyte stability.
Calculating the SD is also easy. Check out our video on SD if you need more information.
It's important to keep in mind that the estimates of SDs from month to month can vary greatly
if you have an insufficient number of measurements.
Ideally, you'll get the most valid data set by using six consecutive months of data.
Once you have collected this data, you can fix this mean and SD as your target mean and
SD.
The target mean and SD will be used to identify out-of control conditions.
After the QC target and range has been established, you will be able to create a QC design and
select appropriate QC Rules.
Bio-Rad offers a software feature called Westgard Advisor that will help you define your
QC strategy.
Westgard Advisor can help you identify tests that need improvement, can recommend statistical
process control rules, and the number of control samples to use per run.
We hope you've found this tutorial helpful.
For all of your QC needs visit www.qcnet.com.