Westgard Multirule QC Evaluation (Two Levels, Across Runs)
The classic Westgard multirule for two control levels: 1-3s, 2-2s, R-4s, 4-1s and 10-x reject a run, with 1-2s as a warning only and never a rejection.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Level 1 mean
- 100
- Level 1 SD
- 2
- Level 2 mean
- 200
- Level 2 SD
- 4
- This run's level 1 result
- 105
- This run's level 2 result
- 209
Result: Run rejected: 2-2s.
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Level 1 mean
- Level 1 SD (above zero)
- Level 2 mean
- Level 2 SD (above zero)
- This run's level 1 result
- This run's level 2 result
- Level 1 previous runs, oldest first, one result per line
- Level 2 previous runs, oldest first, one result per line
How this is calculated
Citation
Westgard JO, Barry PL, Hunt MR, Groth T. A multi-rule Shewhart chart for quality control in clinical chemistry. Clin Chem 1981;27:493-501. Rule statements read in the first author's own account, "Westgard Rules and Multirules" (westgard.com): 1-3s, 2-2s, R-4s, 4-1s and 10-x reject; 1-2s warns. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.