Glucose Predictions
⚠️ IMPORTANT WARNING
THIS IS A HIGHLY EXPERIMENTAL FEATURE!
- DO NOT depend on these predictions for medical decisions
- DO NOT use predictions in real-life diabetes management
- This feature is for research and testing purposes only
- We take NO RESPONSIBILITY for any consequences of using this feature
- Always consult your healthcare provider and use approved medical devices
The prediction feature is provided as-is without any warranties. Use at your own risk.
Overview
Trndi includes an experimental glucose prediction engine that attempts to forecast future blood glucose values based on recent readings and trends. This feature must be explicitly enabled in settings.
How It Works
Prediction Algorithm
The prediction engine uses recent CGM readings to calculate trends and project future glucose values. The algorithm:
- Analyzes recent readings - Uses your latest CGM data points
- Calculates trends - Determines the rate of change (mg/dL per minute)
- Projects forward - Estimates glucose values at future time points
- Generates multiple predictions - Creates forecasts for approximately 5, 10, and 15 minutes ahead
Trend Classification
Predictions are classified into trend categories based on the rate of change (delta) in mg/dL over the prediction interval:
| Trend |
Delta (mg/dL) |
Arrow |
Description |
| Double Up |
≥ +15 |
↑↑ |
Rising very fast (≥3 mg/dL/min) |
| Single Up |
+10 to +15 |
↑ |
Rising fast (2-3 mg/dL/min) |
| Forty-Five Up |
+5 to +10 |
↗ |
Rising slowly (1-2 mg/dL/min) |
| Flat |
-5 to +5 |
→ |
Steady (-1 to +1 mg/dL/min) |
| Forty-Five Down |
-10 to -5 |
↘ |
Falling slowly (-2 to -1 mg/dL/min) |
| Single Down |
-15 to -10 |
↓ |
Falling fast (-3 to -2 mg/dL/min) |
| Double Down |
≤ -15 |
↓↓ |
Falling very fast (≤-3 mg/dL/min) |
Display Modes
Full Mode (Default)
When predictions are enabled, the full mode displays detailed information for three time points:
⏱5' ↗ 145.2 | ⏱10' → 147.8 | ⏱15' ↘ 146.1
Each prediction shows:
- ⏱ Clock icon with minutes ahead
- Trend arrow (detailed: ↑↑, ↑, ↗, →, ↘, ↓, ↓↓)
- Predicted glucose value in your configured unit
Short Mode
Short mode (predictions.short) provides a simplified at-a-glance view showing only the middle prediction (around 10 minutes ahead) with a larger, simplified arrow:
- ↗ - Glucose rising (any upward trend)
- → - Glucose steady (flat trend)
- ↘ - Glucose falling (any downward trend)
The simplified arrows map multiple trend levels:
- Rising (↗): Includes FortyFiveUp, SingleUp, and DoubleUp
- Steady (→): Includes Flat
- Falling (↘): Includes FortyFiveDown, SingleDown, and DoubleDown
The arrow is automatically scaled larger for better visibility.
Configuration
Enable Predictions
- Open Settings
- Navigate to the “Predictions” section
- Check “Show glucose predictions”
- (Optional) Check “Show only trend arrows (short mode)” for simplified display
Settings
predictions.enable - Enable/disable predictions (default: false)predictions.short - Use simplified arrow display (default: false)predictions.short.size - Short-mode arrow size (integer). Use 1 for small (default), 2 for medium, 3 for big. The numeric value controls the UI scale/area used when showing only a single arrow.
Limitations
- Accuracy varies - Predictions are estimates and may not reflect actual future values
- Limited timeframe - Only forecasts 5-15 minutes ahead
- Requires recent data - Needs sufficient recent CGM readings
- Cannot predict events - Does not account for food, insulin, exercise, or other factors
- Stale data - Predictions are not shown when CGM data is outdated
Technical Details
Extensions Access
Extensions can access predictions via the JavaScript Extensions Engine:
// Predict the next 3 readings (default)
const predictions = Trndi.predictReadings();
// Predict the next 5 readings
const predictions = Trndi.predictReadings(5);
// Each prediction contains:
// [value_in_current_unit, mgdl, mmol, timestamp]
See Extensions API for more details.
Update Frequency
Predictions are recalculated whenever:
- New CGM readings arrive
- Settings are changed
- The display is refreshed
Best Practices
- Never make treatment decisions based solely on predictions
- Use as a supplementary tool for awareness only
- Monitor actual CGM readings as your primary data source
- Understand the limitations of trend-based forecasting
- Disable if not needed to reduce UI clutter
Troubleshooting
Predictions show “?”
- Not enough recent readings available
- Data quality issues
- API unable to generate prediction
“Predictions Unavailable”
- Insufficient data points for prediction
- CGM connection issues
- Check that your data source is working correctly
Remember: This feature is experimental. Always rely on your CGM device and healthcare provider’s guidance for diabetes management decisions.