A time Dexcom G5

Is the dexcom g5 15 minutes ahead of capillary blood sugar or is it behind? Can some one answer this question?

Dexcom is lagging.

Depends on individual and metabolism but there is a lag. 10-20 minutes. Sometimes more depending on last food intake time and carbs. Also huge difference if CGM has up or down arrow rather than last 15 minutes steady flatline results.

Behind, and if you are quite low, the lag when your bg comes up fast can be quite long, falsely indicating that you are still low, so watch out so that you don’t repeat carb intake unnecessarily.


Like everything diabetes, it depends. If your BG has been steady for 15 or 20 minutes, your capillary blood sugar has already caught up. You should get the same result.