ValidToolsLab.com
Westgard QC Rules Advisor — Six Sigma Based
Recommendation
Report Number
VTL-QRA-20260824-6B1E
Date: 2026-08-24
✅ Approved
🎯 QC RULES ADVISOR — Troponin I · Abbott Alinity i
📊 Six Sigma Scale
σ<3
Poor
Poor
σ3–4
Marginal
Marginal
σ4–5
Good
Good
σ5–6
Excellent
Excellent
σ≥6
World Class
World Class
σ5.58
Mean Sigma
σ4.38
Worst Level
2
Control Levels
Daily
Frequency
✅ Recommended QC Strategy
🎯
Good — σ4.38
Westgard multirule — 2 controls/day, full rule set.
Recommended Rules:
1₂.₅s
2₂s
R₄s
4₁s
10x̄
Controls/Day
2
False Rejection (Pfr)
2%
Error Detection (Ped)
90%
Description: Standard Westgard multirule (1₂s warning + 2₂s / R₄s / 4₁s / 10x̄ rejection). Good balance between error detection and false rejections.
Recommended Action:
Review calibration and reagent handling. Quarterly review.
📋 QC Rule Definitions
1₂.₅s
Warning: 1 control exceeds ±2.5SD
2₂s
Reject: 2 consecutive controls exceed ±2SD (same side — systematic error)
R₄s
Reject: Range between 2 controls exceeds 4SD (random error)
4₁s
Reject: 4 consecutive controls exceed ±1SD (same side — systematic trend)
10x̄
Reject: 10 consecutive controls on same side of mean (systematic shift)
📊 Results per QC Level
Level 1 (Low, ~0.5 ng/mL)
σ4.38 — Good
TEa
±20.0%
Bias
+2.50%
CV%
4.0%
Pred TE
9.1%
σ
4.38
Allowable CV ≤ 5.0% · Allowable Bias ≤ ±10.0% · SEa = 10.0% ·
REa = 10.0%
1₂.₅s
2₂s
R₄s
4₁s
10x̄
Daily · 2
controls
Level 2 (High, ~5.0 ng/mL)
σ6.79 — World Class
TEa
±20.0%
Bias
+1.00%
CV%
2.8%
Pred TE
5.62%
σ
6.79
Allowable CV ≤ 5.0% · Allowable Bias ≤ ±10.0% · SEa = 10.0% ·
REa = 10.0%
1₃s
Daily · 2
controls
📋 Clinical Interpretation
EXCELLENT QC DESIGN (Mean σ = 5.58). Troponin I on Abbott Alinity i: Simple QC rules with 2 control levels run daily are sufficient. Recommended: 1₂.₅s / 2₂s / R₄s / 4₁s. High sigma processes rarely produce unreported errors with standard QC.
References:
Westgard JO. Six Sigma Quality Design & Control, 2nd ed. 2006 ·
Westgard JO, et al. Clin Chem 1981;27:493–501 ·
CLSI C24-A4 — Statistical QC for Quantitative Measurement Procedures
Formula: σ = (TEa − |Bias|) / CV · Recommendation based on σ tier: ≥6=World Class, 5–6=Excellent, 4–5=Good, 3–4=Marginal, <3=Poor
Note: QC rule recommendations are based on probability theory. Final QC design should be reviewed by the laboratory director per CLIA §493.1256 and CAP GEN.55500.
Formula: σ = (TEa − |Bias|) / CV · Recommendation based on σ tier: ≥6=World Class, 5–6=Excellent, 4–5=Good, 3–4=Marginal, <3=Poor
Note: QC rule recommendations are based on probability theory. Final QC design should be reviewed by the laboratory director per CLIA §493.1256 and CAP GEN.55500.
Electronically Signed By: Maria Gonzalez, MLS(ASCP), MLS-004821
Chemistry
Date: 2026-08-24 13:25
Maria Gonzalez, MLS(ASCP)
Medical Laboratory Technologist / Analyst Signature
Submitted: 2026-08-24T13:25
Medical Laboratory Technologist / Analyst Signature
Submitted: 2026-08-24T13:25
Electronically Signed By: Dr. Jane Sample, MD, MD-119284
Director / Supervisor of Clinical Laboratory
Date: 2026-08-25 09:05
Dr. Jane Sample, MD
Laboratory Director Approval Signature
Approved: 2026-08-25T09:05
Laboratory Director Approval Signature
Approved: 2026-08-25T09:05
Example Regional Medical Center — Clinical Laboratory
123 Laboratory Way, Sample City, ST 00000
CLIA: 00D0000000
· State Lic.: CLS-000000
· (555) 000-0000
Laboratory Director: Dr. Jane Sample, MD
Example Regional Medical Center — Clinical Laboratory
Generated by ValidToolsLab · CLIA §493.1256 Compliant
Report: VTL-QRA-20260824-6B1E · 2026-08-24