Dexcom time lag, and interstitial fluid glucose vs BG

[Michel]

@MM2

So is the value that is displayed on receiver what Dexcom projects is blood glucose right now, based on tissue glucose that sensor filament is measuring plus trend. ??

What I thought until you posted your question:

• The glucose level in the interstitial fluid is 10-20 minutes behind the BG

• calibration matches the interstitial fluid glucose to BG, but does not remove the delay

• the Dexcom shows a number that is 15 minutes behind the real BG.

I was going to post in that sense, but I actually reviewed some scientific literature, and, as of 2014, the papers are saying that the Dexcom number is estimating the BG right now (not 15 minutes behind).

I am not 100% sure what is reality today. I need to do more research

@MM2

I have seen comments suggesting display value is based on current tissue glucose measurement, so wait 15 minutes to see a value that should match closer to BG meter.

I had always assumed that was true (and somewhat verified by experience) until you asked

@MM2

And for those using xDrip, what does it report ?.

I am pretty sure that xDrip reports the BG 15 minutes ago, as estimated from the interstitial fluid. But confirmation should come from the experts: @docslotnick, @dm61, what do you think?