Active QC Failures
| Instrument | Test | Level | Status | Latest Z | Rejections | Rules Triggered | Last Run |
|---|---|---|---|---|---|---|---|
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Westgard Rules Reference
These six rules define when a QC run is considered out of control. Applied with tiered time windows.
1-2s
Warning
One value exceeds 2 standard deviations. Investigate but do not reject.
|z| > 2.0
1-3s
Rejection
One value exceeds 3 standard deviations. Reject the run immediately.
|z| > 3.0
2-2s
Rejection
Two consecutive values exceed 2 SD in the same direction. Systematic bias.
2 consecutive z > 2.0
R-4s
Rejection
Range between two consecutive values exceeds 4 SD. High random error.
range > 4σ
4-1s
Rejection
Four consecutive values all exceed 1 SD in the same direction. Instrument drift.
4 consecutive |z| > 1.0
10x
Rejection
Ten consecutive values on the same side of the mean. Strong systematic bias.
10 consecutive same sign