Westgard Multirule System n n a multi-rule system

Westgard Multirule System n n a “multi-rule” system developed by Dr. James O. Westgard based on statistical concepts a combination of decision criteria or rules to assess if a system is in control use when at least 2 levels of control are run with the examination run cannot use with only one control Dr. Westgard Quantitative QC-Module 7 1

Westgard Multirule System Titles n 12 S rule n 13 S rule n 22 S rule n R 4 S rule n 41 S rule n 10 X rule Quantitative QC-Module 7 Used when 2 levels of control material are analyzed per run. 2

Westgard – 12 S Rule WARNING RULE – not cause for rejecting a run n One of two control results falls outside ± 2 SD n Alerts technologist to possible problems n Must then evaluate the 13 S rule n Quantitative QC-Module 7 3

Westgard – 22 S Rule Two consecutive control values for the same level fall outside of ± 2 SD in the same direction, or n Both controls in the same run exceed ± 2 SD. n Patient results cannot be reported. n Requires corrective action n Quantitative QC-Module 7 Quantitative QC - Module 8 4

Westgard – R 4 S Rule One control exceeds the mean by – 2 SD, and the other control exceeds the mean by +2 SD. n The range between the two results will therefore exceed 4 SD. n Random error has occurred, test run must be rejected. n Quantitative QC-Module 7 5

Westgard – 41 S Rule requires control data from previous runs n four consecutive QC results for one level of control are outside ± 1 SD, or n both levels of control have consecutive results that are outside ± 1 SD. n Quantitative QC-Module 7 6

Westgard – 10 X Rule requires control data from previous runs n ten consecutive QC results for one level of control are on one side of the mean, or n both levels of control have five consecutive results that are on the same side of the mean n Quantitative QC-Module 7 7

Westgard Multirule QC Quantitative QC-Module 7 8

Activity Using the Westgard Multirule System, describe the control values for each day in the following slide. Quantitative QC-Module 7 9

Quantitative QC-Module 7 10

Answers for activity n Day 21, 22, 24, 26, 27, 30, 31, 33, 34, 36 -44 – in control Day n 23, 28, 29 – 12 s 25 - 13 s 32 – 22 s 35 - R 4 s Quantitative QC-Module 7 11