Automated Westgard multi-rule evaluation software

What are Westgard multi-rules?

Westgard multi-rules are a set of statistical control rules used to decide whether an analytical run is in control. Instead of a single 2SD limit (which rejects too often), a combination of rules improves error detection while limiting false rejection. The common set includes 1_2s (warning), 1_3s, 2_2s, R_4s, 4_1s, 8_x and 10_x.

Within-run, across-run and across-material

Rules are not all applied the same way. R_4s is a within-run rule (range across levels in the same run). 2_2s, 4_1s, 10_x can be applied across consecutive runs and, where appropriate, across materials (pooling control levels using SDI). Applying rules at the wrong scope causes both missed errors and false alarms — QCnomics applies each rule at its correct scope automatically.

CLSI C24-A4 phased QC

QCnomics implements the CLSI C24-A4 phased approach: a verification phase for the first runs of a new lot, a provisional phase as data accumulates, and a fixed phase once the mean and SD are locked (typically after 20 in-control runs). The active rule set and limits are selected automatically based on run count and lot.

What QCnomics does for you

• Evaluates every QC entry in real time and logs violations with the exact rule triggered.
• Plots multi-level Levey-Jennings charts with shifts and trends highlighted.
• Links each violation to root-cause analysis and CAPA for the accreditation record.
• Uses the manufacturer mean or locks the mean after 20 chronological runs per lot.

Frequently asked questions

Which Westgard rules should a clinical chemistry lab use?

A common, well-balanced set is 1-3s / 2-2s / R-4s / 4-1s / 10x, with 1-2s as a warning only. QCnomics lets you enable the rules appropriate to each analyte and applies them at the correct within-run/across-run scope.

Does QCnomics reduce false rejections?

Yes. By using multi-rule logic instead of a blanket 2SD cutoff and by applying rules at the correct scope and phase, it flags genuine out-of-control situations while avoiding unnecessary repeat testing.

Is it aligned with CLSI C24-A4?

Yes — the verification, provisional and fixed phases and the mean/SD locking follow CLSI C24-A4 guidance.

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