![]() Issues in using multirule QC procedures.This article is exclusively sponsored by LGC Technopath Clinical Diagnostics See how the multirule QC should be done (and find out if you've been doing it right yourself). Westgard walks you through a Levey-Jennings chart day by day, plotting the control data and pointing out which run violates which rule. How do you use them? This lesson combines basic QC theory and practice to show you how. This is an important diagnostic tool because it will prevent a company from continuing to run more and more processes where there is something that is likely wrong, which can create a lot of waste.Those "Westgard rules" can be confusing. The rules do not help to identify the specific problem, but rather just raise the flag that there is something wrong somewhere in the process. If it is just with the parts being used, the run may need to be redone with different parts.Įvery company that uses the Westgard Rules will need to determine what the most likely cause of deviations like this will be. If the problem is with the machine itself, it may need to be fixed. 10 Consecutive measurements are on the same side of the mean.Īs you can see, these are all different types of unexpected results if there were just randomness involved.Four consecutive measurements exceed 1 standard deviation on the same side of the mean.Two measurements in the same run have a 4 standard deviation difference (such as one exceeding 2 standard deviations above the mean, and another exceeding 2 standard deviations below the mean).Two consecutive measurements exceed 2 standard deviations of the reference range, and on the same side of the mean.One measurement exceeds 3 standard deviations either above or below the mean of the reference range.One measurement exceeds 2 standard deviations either above or below the mean of the reference range.If the results of an analysis are outside of the Westgard Rules, therefore, it should indicate that there is likely something faulty in the precision or accuracy in the machine or process in question. The rules are all related to statistical patterns and how likely they are to occur with just random variability. He published the rules in his book and discussed them extensively during his seminars on quality control. The Westgard Rules were originally developed by James Westgard. Facility Efficiency TPM Lean Manufacturing show all tags ![]()
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