Levey–Jennings Chart Templates: A Guide to Free Quality Control Tools Abstract Levey–Jennings (L-J) charts are a cornerstone of statistical quality control in clinical laboratories and other testing environments. They allow analysts to visualize assay performance over time, detect systematic and random errors, and ensure compliance with regulatory standards. While commercial software exists, free Levey–Jennings chart templates—available in spreadsheet programs like Microsoft Excel and Google Sheets—offer an accessible, cost-effective solution. This paper explains the construction and interpretation of L-J charts, reviews the best free template sources, and provides practical guidance for implementation. 1. Introduction Quality control (QC) in laboratory medicine relies on monitoring control materials with known values. The Levey–Jennings chart, introduced in the 1950s as a modification of the Shewhart control chart, plots control results against time or run number, with horizontal lines representing the mean and control limits (typically ±1, ±2, and ±3 standard deviations). A free, well-designed template enables small to mid-sized labs, educational institutions, and research settings to implement QC without expensive software. 2. Key Components of a Levey–Jennings Chart | Component | Description | |-----------|-------------| | X-axis | Time sequence (run number, date, or batch ID) | | Y-axis | Control result value (concentration, activity, etc.) | | Central line | Mean (target value) of the control material | | Warning limits | ±2 SD (often dashed lines) | | Action limits | ±3 SD (solid lines) | | Data points | Individual control results connected by lines | | Violation markers | Colors or annotations for Westgard rule failures | 3. Constructing a Free Levey–Jennings Template in Excel/Sheets A free template typically includes pre-programmed formulas. Here is how to build one or verify a downloaded template: Step 1 – Data Input
Column A: Run number / date Column B: Control result (e.g., glucose control level 1)
Step 2 – Calculate Statistics
Mean: =AVERAGE(B2:B100) Standard Deviation: =STDEV.S(B2:B100) +1 SD, +2 SD, +3 SD, and their negative equivalents levey jennings chart template free
Step 3 – Create the Chart
Select date/run column and control results Insert a Line with Markers chart Add constant lines for mean, ±1 SD, ±2 SD, ±3 SD (using additional series with identical x-values)
Step 4 – Apply Westgard Rules (optional but recommended) Use conditional formatting or helper columns to flag when: Levey–Jennings Chart Templates: A Guide to Free Quality
1 result > ±3 SD (13s) 2 consecutive results > ±2 SD (22s) 4 consecutive results on same side of mean (41s) 10 consecutive results on same side of mean (10x)
4. Where to Find Free Levey–Jennings Chart Templates Several reputable sources offer free, ready-to-use templates (always verify formulas for your specific control limits): | Source | Format | Features | |--------|--------|----------| | Westgard QC Website (westgard.com) | Excel .xlsx | Built-in Westgard rules, multi-level controls | | CLSI (Educational section) | Excel, PDF guide | Compliant with CLSI C24 guidelines | | Github / LabLibraries | Excel, Google Sheets | Open-source, editable, often with example data | | ACLPS (Association for Clinical Pathology) | Excel | Simple, beginner-friendly | | Vertex42 (vertex42.com) | Excel | Clean design, printable charts | Note: Always download from official or verified educational domains to avoid macro viruses or miscalculations. 5. Example of a Free Template Structure A high-quality free template will include these sheets:
Data Entry – Enter control results by run. Chart View – Auto-updating L-J chart with colored limit lines. Summary Stats – Current mean, SD, CV%, number of runs. Violation Log – Lists dates and types of QC rule failures. Instructions – Clear steps for resetting or extending the template. This paper explains the construction and interpretation of
6. Interpreting the Chart – When to Reject a Run Using free templates, technicians should reject a run when: | Violation | Indication | Action | |-----------|------------|--------| | 13s | Random error | Reject run, troubleshoot | | 22s | Systematic error | Check calibration, reagents | | 41s | Shift | Review instrument stability | | 10x | Long-term drift | Recalibrate | A properly designed free template will highlight these violations automatically using red markers or cell alerts. 7. Limitations of Free Templates
No real-time data logging – Manual entry required (unlike LIS-integrated software). No multi-rule automatic probability calculations – Some complex rules require manual review. User error risk – Formulas can be accidentally overwritten. Limited scalability – Best for ≤5 control materials.