Troubleshooting Common Sensor Errors

Understanding Error Types

CGM errors fall into two main categories: technical failures and physiological artifacts.

Compression Lows (PISA)

Pressure-Induced Sensor Attenuation occurs when pressure restricts blood flow to the sensor site.

Symptoms

• False low readings, usually during sleep
• "Sensor error" messages
• Readings that don't match how you feel

Solutions

• Reposition during sleep
• Avoid placing sensor where you typically rest
• Use alternate sites

Lag Time Issues

The 5-15 minute lag between blood and interstitial fluid is normal, not an error.

Avoiding Problems

• Don't calibrate during rapid glucose changes
• Wait for stability before making treatment decisions
• Use fingersticks to confirm during rapid flux

Interfering Substances

Common Culprits

• Acetaminophen: Can cause false highs (improving in newer sensors)
• Vitamin C: May affect some sensors
• Hydroxyurea: Contraindicated with most CGMs

Mechanical Issues

Filament Problems

• Pull-out: Sensor becomes dislodged
• Kinking: Improper insertion angle
• Solution: Replace sensor

Bio-fouling

• Bleeding during insertion can affect early readings
• Usually resolves within 24 hours

When to Replace

Replace your sensor if:

• Persistent error messages after troubleshooting
• Readings consistently don't match fingersticks
• Physical damage to sensor or adhesive
• Skin reaction at insertion site