What are the 5 Westgard rules?
What are the 5 Westgard rules?
Westgard rules
| Rule | Criteria |
|---|---|
| R4s | 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). |
| 41s | 4 consecutive measurements exceed 1 standard deviation on the same side of the mean. |
What is a Levey Jennings plot?
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. The date and time, or more often the number of the control run, is plotted on the x-axis.
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.
What is a shift in Levey Jennings chart?
A shift is a sudden change of values from one level of the control chart to another. The occurrence of shifts and trends on the Levey-Jennings control chart is the result of either proportional or constant error.
How many rules does the Westgard scheme have?
The well-known Westgard multirule QC procedure uses 5 different control rules to judge the acceptability of an analytical run.
What is a shift on a Levey Jennings chart?
What are the control limits of a Levey Jennings chart?
The Levey-Jennings chart uses its own subset of these rules: One of one point is outside of +- 3-sigma control limits – 13s. Two of two points outside +-2-sigma control limits – 22s. Four of four points outside +-1-sigma control limits – 41s.
What is a shift in Levey-Jennings chart?
Which Westgard rules are random error?
13s: This rule applies when a control result falls outside of the 3s limit, either above or below the mean. The run should be rejected. Usually, this indicates that a random error has occurred. 22s rule: This rule applies when two consecutive results exceed the +2 or the -2 standard deviation limit.
