What are the warning Westgard rules?

One measurement exceeds 2 standard deviations either above or below the mean of the reference range. One measurement exceeds 3 standard deviations either above or below the mean of the reference range.

Which Westgard rule violations point to 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.

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.

Is R4s a random error?

R4s indicates a rejection when one control measurement in a run exceeds a +2s control limit and another exceeds a -2s control limit. This “range” rule is sensitive to changes in the width of the distribution, therefore it is a good indicate of increases in random error or changes in the precision of the method.

How many Westgard rules are there?

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.

What is the difference between shift and trend?

A shift is a sudden change of values from one level of the control chart to another. A common cause of a shift is failure to recalibrate when changing lot numbers of reagents during an analytical run. A trend is a continuous movement of values in one direction over six or more analytical runs.

What is 4s rule?

What type of error is r4s?

Run 14 The control results for the high material exceeds its +2s limit and the control result for the low material exceeds its -2s limit, therefore an R4s rule violation has occurred. This most likely indicates a random error.

What are the Westgard rules?

“Westgard rules” are generally used with 2 or 4 control measurements per run, which means they are appropriate when two different control materials are measured 1 or 2 times per material, which is the case in many chemistry applications.

What to do if a control rule is violated?

Interpretation of warning rule. If both control results are within 2s limits, report the patient test results. If one control result exceeds a 2s limit, inspect the control data as follows and reject the run if any control rule is violated Within run inspection of control results.

How do you use a 1 2s warning rule?

Use a 1 2s warning rule and the 1 3s /2 2s /R 4s /4 1s /10 x rejection rules with 2 control measurements per run. Analysis of control materials. Analyze one sample of the Level A control and one sample of the Level B control in each run. Interpretation of warning rule. If both control results are within 2s limits, report the patient test results.

What is an R 4s rule violation in run 14?

Run 14 The control results for the high material exceeds its +2s limit and the control result for the low material exceeds its -2s limit, therefore an R 4s rule violation has occurred. This most likely indicates a random error.