Westgard rules on one control
Paste control results in run order. 1-2s is a warning. 1-3s, 2-2s, R-4s, 4-1s and 10x are the usual reject rules. Confirm the SOP your lab actually runs.
- 1-2s — Point 1 is 2.50 SD (warning)
- 1-2s — Point 2 is 2.60 SD (warning)
- 2-2s — Points 1–2 are both beyond 2 SD on the same side
Questions
Which Westgard rules reject a run?
1-3s, 2-2s, R-4s, 4-1s, and 10x are the usual reject rules. 1-2s is a warning: one point beyond two standard deviations.
How do I enter a control chart?
Enter the target mean and the standard deviation, then paste the control results in run order. Separate values with commas or new lines.
Does this replace a laboratory SOP?
No. A lab follows the multirule written in its procedure. This page only checks one control series against the common Westgard rules.
Educational only. Not medical advice, not a regulatory determination, and not a substitute for qualified RA/QA, legal, clinical, or statistical counsel. Westgard QC does not submit to FDA, Notified Bodies, or IRBs.