What are Westgard Rules? Westgard Rules are multirule QC rules to help analyze whether or not an analytical run is in-control or out-of-control. It uses a combination of decision criteria, usually 5 different control rules to judge the acceptability of an analytical run.
How do you explain Levey-Jennings chart?
A Levey–Jennings chart is a graph that quality control data is plotted on to give a visual indication whether a laboratory test is working well. The distance from the mean is measured in standard deviations. It is named after Stanley Levey and E. R.
What are the control limits of a Levey-Jennings chart?
13s corresponds to a Levey-Jennings chart having control limits set as the mean plus/minus 3s. An analytical run is rejected when a single control measurement exceeds a 3s control limit.
When two consecutive controls are greater than 2 SD units from the mean what should you do first?
Westgard rule 22s states that if two consecutive control measurements across runs exceed the same mean -2 standard deviations (SD) or exceed the same mean +2SD, or, within a run, if two consecutive control values are outside the same 2 SD, the run must be rejected.
How many Westgard rules are there?
The well-known Westgard multirule QC procedure uses 5 different control rules to judge the acceptability of an analytical run.
How are Westgard Rules calculated?
It is calculated by taking the difference between the control result and the expected mean, then dividing by the standard deviation observed for that control material.
What is R4S rule?
Westgard Rule R. 4s The R4s rule applies to controls within a run. If two controls exceed 4SD, that is, if one control exceeds +2SD and the other control (or another control, if more than 2 controls are tested) exceeds -2SD, the run should be rejected.
Which Westgard rules are random error?
Random error is usually indicated by the 13s or R4srules, whereas systematic error is more likely indicated by the 22s,41s, or 10x rules. Refer to trouble-shooting guides to identify possible causes for the type of error indicated by the control rule that was violated.
What is a shift on a Levey Jennings chart?
By plotting quality control results on a Levey-Jennings chart, shifts and trends in the quality control results can be quickly discovered. A shift occurs when the quality control results are all distributed on one side of the mean or the other for 5 to 7 consecutive days. Shifts occur because of systematic error.
What is r4s rule?
What is the Levey-Jennings 1/1 2s rule?
1 2s refers to the control rule that is commonly used with a Levey-Jennings chart when the control limits are set as the mean plus/minus 2s. In the original Westgard multirule QC procedure, this rule is used as a warning rule to trigger careful inspection of the control data by the following rejection rules.
How do you judge control status in a Levey Jennings chart?
Control status will be judged by either the 1 2s or 1 3s rule. These rules are defined as follows: 1 2s refers to the control rule that is commonly used with a Levey-Jennings chart when the control limits are set as the mean plus/minus 2s.
What is Westgard rule 2 2s?
Westgard Rule 2 2S. Westgard rule 2 2s states that if two consecutive control measurements across runs exceed the same mean -2 standard deviations (SD) or exceed the same mean +2SD, or, within a run, if two consecutive control values are outside the same 2 SD, the run must be rejected.
What does 13s mean on a Levey-Jennings chart?
You can click on a graphic to get a larger picture that more clearly illustrates the application of each control rule. 13s refers to a control rule that is commonly used with a Levey-Jennings chart when the control limits are set as the mean plus 3s and the mean minus 3s.
