The term R:4S means that when a control rule is triggered, which statement is true about the run?

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Multiple Choice

The term R:4S means that when a control rule is triggered, which statement is true about the run?

R 4S looks at the spread between two consecutive control measurements within a single run. If the range between those two results is greater than 4 standard deviations, the run is flagged as out of control. This means two consecutive controls in the same run are more than 4 SD apart, which is exactly the scenario described by the correct statement. This rule is useful for catching abrupt, one-off errors within a run, such as a transient instrument or reagent issue affecting one measurement. The other options describe different QC criteria (individual points beyond 4 SD, four consecutive points on the same side, or a four-consecutive-shift pattern) and do not match what the R 4S rule specifies.

R 4S looks at the spread between two consecutive control measurements within a single run. If the range between those two results is greater than 4 standard deviations, the run is flagged as out of control. This means two consecutive controls in the same run are more than 4 SD apart, which is exactly the scenario described by the correct statement.

This rule is useful for catching abrupt, one-off errors within a run, such as a transient instrument or reagent issue affecting one measurement. The other options describe different QC criteria (individual points beyond 4 SD, four consecutive points on the same side, or a four-consecutive-shift pattern) and do not match what the R 4S rule specifies.

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