Running internal quality control doesn’t mean juggling paper logs, manual Z-score calculations, and a separate spreadsheet for trend charts.

Lab Test Academy’s LJ-Westgard QC Tool brings all of that into one browser-based workspace, so any medical laboratory technologist can plot a Levey-Jennings chart, apply Westgard multi-rules, and keep a running QC log without extra software.

Here’s a simple walkthrough for getting the most out of it.

Levey–Jennings Chart with Westgard Rules + Daily Log
🧪 LJ–Westgard QC Tool Plot Levey–Jennings charts, apply Westgard multi-rules, and log daily QC values to track trends over time.
1Enter QC values in the Data Input box, or use the Daily Log to add one value per day.
2Click Plot Chart — or in the Daily Log, click Plot from Log to chart all saved entries.
3Review the LJ chart, Westgard rules, and the overall QC decision.
4Export a PDF report or save a session for trend comparison.
Quality Control Analytics Levey–Jennings Chart with Westgard Multi-Rules Engine & Daily Log
LJ Chart & Westgard Rules Daily QC Log Saved Sessions PDF Export
Session Details
Laboratory Name
Analyst Name
Test Name
Month/Year
Select month & year
Data Input
Please enter at least 2 numeric values.
Custom Mean & SD Override calculated values with your own reference
📅 Daily QC Log
Daily QC Value Log AUTO-SAVED
Date
QC Value
Please enter a valid date and numeric value.
Tip: Add one QC value per day. Use Plot from Log to generate the LJ chart from all saved entries in date order.
Entries are automatically saved in your browser's local storage and will persist when you close or refresh this page.
# Date QC Value Z-Score Status
No entries yet.
Add a date and value above to start your daily log.
📊 Saved Sessions
Sessions — Compare by Date
No saved sessions yet. Click Save Session after plotting.

Step 1: Set Up Your Session Details

Before entering any values, fill in the basic session information — laboratory name, analyst name, test name, and the month/year being tracked. This keeps every chart properly labeled, which matters later if you’re comparing sessions or attaching the export to an audit file.

Step 2: Enter Your QC Data
You have two ways to get values into the tool:
Data Input box — paste or type in a batch of QC values at once. You’ll need at least two numeric values before the tool can calculate a mean and standard deviation. Daily Log — add one QC value per day as your instrument produces it. Each entry is timestamped and auto-saved in your browser, so you can build up a full month’s log entry by entry without losing data on refresh.

If your control material already has an established mean and SD from the manufacturer or your own cumulative data, use the Custom Mean & SD override fields instead of letting the tool calculate them from a short run.

Internal Quality Control Tools

Step 3: Plot the Chart

Click Plot Chart to generate the Levey-Jennings plot from the Data Input box, or Plot from Log to chart everything saved in your Daily Log, arranged automatically in date order. The chart displays your mean line along with ±1 SD, ±2 SD, and ±3 SD boundaries, and color-codes each point as in-control, warning, or reject.

Internal Quality Control Tools

Step 4: Read the Westgard Rule Interpretation

This is where the tool saves the most time. Instead of manually checking each Westgard rule against your data points, the engine evaluates the multi-rule set automatically and flags any violations alongside an overall QC decision — accept the run or investigate before releasing patient results.

Step 5: Track Trends and Export Records

Once you’re done reviewing:

  • Export CSV or Export PDF to keep a permanent, shareable record for your quality file or ISO 15189 audit trail.
  • Save Session to store the run for later comparison — the tool can chart mean trends across multiple saved sessions, which is useful for spotting slow drift across months.
  • Import CSV if you already maintain QC data elsewhere and want to bring it into the tool for analysis.
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