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Safety tips to avoid faulty readings with CGM and Finger sticks

Continuous Glucose Monitors (CGMs) are revolutionary tools for managing diabetes, providing real-time glucose readings and trends. However, ensuring accuracy and reliability can sometimes be challenging. Here are some expert tips to help you protect against faulty readings.

Accuracy Tips

Calibration is Key:

Always wash your hands thoroughly before taking a fingerstick reading. Dirty hands can lead to inaccurate blood glucose (BG) meter readings, which can then lead to incorrect CGM calibrations.

If handwashing isn’t possible, wipe away the first drop of blood and use the second drop for a more accurate reading.

Confirm with Fingersticks:

When CGM and fingerstick readings differ significantly, rewash your hands and take another fingerstick to confirm accuracy. This is crucial, especially before making insulin dosing decisions.

Timing Matters:

Avoid calibrating your CGM when your glucose levels are low or rapidly changing. These periods can drive worse accuracy. Ideal times for calibration are when glucose levels are stable, such as in the morning or before bed.

Day One Patience:

CGMs tend to have higher inaccuracies on the first day of sensor insertion. Approach day one with caution, especially for insulin dosing. Accuracy generally improves after the first 24 hours.

Pre-Warm Sensors:

To improve day one accuracy, consider inserting a new sensor but delaying the official sensor warm-up for several hours while your current sensor is still active. This "soaking the sensor" method can significantly enhance initial readings.

Monitor Trends and Alarms:

Pay attention to trend arrows and alarms. They are designed to help you manage your glucose levels more effectively. Adjust your insulin doses based on these trends to prevent high or low blood glucose levels.

Safety Precautions


Always maintain good hygiene when handling CGM devices. Clean the sensor insertion site properly and ensure your hands are clean to prevent infections and ensure accurate readings.

Avoid Overreacting:

Resist the urge to overcorrect high readings with large doses of insulin, especially if you are using an insulin pump. Consider the amount of active insulin in your system before making additional corrections.

Double-Check Low Readings:

CGMs can lag behind blood glucose meters during hypoglycemia. If your CGM shows low glucose levels, confirm with a fingerstick before consuming more corrected carbs.

Dealing with Adhesive Issues

If the sensor adhesive begins to peel off, use medical tape or products like Skin-Tac to secure it. For those with adhesive allergies, consider applying a barrier like Flonase or a Band-Aid Tough Pad before inserting the sensor.

Acetaminophen Warning:

Be cautious when taking medications containing acetaminophen, as it can cause false high readings on some CGM devices, like Medtronic and Dexcom G4/G5. Avoid these products or ignore the sensor readings for 8-10 hours after taking them.


CGMs provide invaluable insights into glucose management, but they require careful handling and a good understanding of how they work. By following these expert tips, you can improve the accuracy and reliability of your CGM, making diabetes management less frustrating and more effective.For more insights on diabetic care, monitoring sugar levels, and healthy living follow Lincoln Health Supply. Let’s together, achieve better health and well-being! 


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