Why did it wait to give me a low alarm?

I’ve got my Dexcom set to do a low alarm when I get below 80.

Last night at about 1 am, it went off. The Dexcom said I was at 59. I took my blood sugar with my meter, and it was spot on - exactly 59. Yay!

But my question this morning is why did it not go off until I was at 59? I downloaded the data, and according to the chart, I first dipped below 80 at 12:15 am, then kept going down until 1am when it woke me.

I’ve had it successfully go off at right below 80 before. Why would it not have done it last night?

Maybe something was in the air last night. Mine woke me about 2:30 that I was high (I have my high alarm set at 120). I took some insulin and went back asleep. I didn’t hear any more alarms until I woke up about 7 - my BS was 170. I was pretty tired last night so I figured it was alarming but I didn’t hear them. Are you a deep sleeper?

Nope, not a deep sleeper at all. I have it set to vibrate then alarm, both me and my husband woke up with the vibrate. So pretty sure I didn’t sleep through it.

We started around the same time and have been having trouble with alarms. They either never go off (my son woke up at 370 - the alarm hadn’t gone off and we are in a hotel - so I’m pretty sure I would have heard it. He’s also had it out of range for more than 20 minutes (what we have set for the alarm) and I pick it up to see that it’s been out of range that long, but it’s never actually alarmed. I’m wondering if there is an issue with the alarm? I think I’ll call Dexcom if it happens again.

Just a thought…double check your alarm settings in case they were somehow either not saved or maybe reset to factory original. In any event, this is a good question for customer service.

As an aside, I would never get any sleep if I set mine to go off below 80! I give myself a lower point so I don’t keep being buzzed awake. But of course that is an individual choice.

Remember there is lag time between blood and ISF, and also when you sleep, im betting you may have slept on the sensor which can slow it down/confuse it since the ISF fluid isnt refreshed as fast…(think of the skin as layers with a scant layer of fluid filling…if its too compressed, the liquid doesnt flow and disperse as easily… or the Dexcom skipped a reading or two,or you hit a button and snoozed it… the dexcom is NOT PERFECT… (mine always tends to read high on me, YMMV)…

But that doesn’t make sense, because the Dexcom itself registered <80 at 12:15 pm, but didn’t alarm until 1am.

I misunderstood you somewhat… My mistake… …thought you were saying it didn’t register it and didnt alarm till later… But it sounds like it might have been snoozed… all kidding aside. you might want to check the alarms and see if they are what you set them at… Iv had an odder thing happen… iv had the dex go off and my blood sugar was fine… not alarm alarm but vibrate…

Barbra, I just read this on the CWD forum and thought I would put it here for you. I missed some alarms the same night that you did and thought it was because I was so tired. Since then, I have missed a couple more & I was extremely tired the one night but not the others. Someone on CWD called Dexcom about missed alarms & they were able to tell by the software how long after the alarm went off that supposedly a button was pressed. They decided that there was a stuck button in her case. Here is the link & it was #4 in that thread.


Interesting (to me) side note on your story. I called and complained that we weren’t hearing alarms. We were getting blind sided by some lows that looked like they should have alarmed several times before we noticed he was low. They had me download the data and send it to them and they were able to tell me when the receiver alarmed and how soon after the button was pushed. I told her “I want access to that data.” She, of course, said “No”.

In any event support told me that, within a suspected time frame, the receiver alarmed and the button was pushed around a second later - several times - that someone was pushing the button after the alarm. I asked her if she had a child and how long did she think it would take a little boy to a) recognize the vibrate alarm and b) dig it out of his pocket and push the button.

We concluded with a suspected stuck button and a replacement meter.