Question 1

Is a CGM more accurate than a fingerstick?

Accepted Answer

Both devices have accuracy limitations. CGMs provide continuous glucose measurements and trends, while fingerstick meters measure blood glucose at a specific moment. Neither is as accurate as laboratory glucose testing.

Question 2

How many minutes behind is a CGM?

Accepted Answer

CGM readings may lag behind blood glucose by several minutes, particularly when glucose rises or falls rapidly. The delay varies by device and conditions.

Question 3

Why is my Dexcom reading higher than my fingerstick?

Accepted Answer

Sensor lag, normal measurement variation, or testing errors may explain the difference. If discrepancies persist when glucose is stable, check your testing technique and follow Dexcom's troubleshooting guidance.

Question 4

Can a CGM show a false low?

Accepted Answer

Yes. Pressure on the sensor can cause falsely low readings. However, unexpected lows should never automatically be dismissed as sensor errors.

Question 5

Should I calibrate my Dexcom G7 daily?

Accepted Answer

No. Dexcom G7 does not require daily calibration. Optional calibration should follow the manufacturer's instructions.

Fingerstick Testing

CGM vs. Fingerstick: Why Blood Sugar Readings Differ