What your alarms mean

Think of alarms as gentle reminders that are always working in the background—so you don’t have to guess what’s happening. 
Man sleeping in bed at night with a FreeStyle Libre sensor on his upper arm and a smartphone showing a glucose alert on the nightstand.

When does FreeStyle Libre system send alarms?

When your glucose goes above or below the threshold you set, alarms11 give you a gentle nudge. You may get an alarm on your smartphone28 at night if your levels drop below your threshold while you’re asleep. 
 

Alarms are optional11 and can be adjusted to be silenced when you need quiet. It’s support that’s designed to move with you, not overwhelm you.

Low glucose alarms.

Smartphone lock screen showing a Low Glucose Alarm notification reading 68 mg/dL with a falling trend arrow.

 

Low glucose alarms sound11,28 when your levels fall below 60mg/dL [3.3mmol/L] / 70 mg/dL [3.9 mmol/L]14. 

 

If your levels fall below [40mg/dL [2.2mmol/L], the Urgent Low Glucose Alarm will sound.

High glucose alarms.

Smartphone lock screen showing a High Glucose Alarm notification reading 261 mg/dL with a rising trend arrow.

 

High glucose alarms appear11,28 when your levels rise above 200mg/dL [[11.1mmol/L]] 250 mg/dL [13.9 mmol/L]14. 

 

If your levels rise above 400mg/dL [[22.2mmol/L] or you are out of range, you’ll get a High Glucose Alarm.

You got an alarm11,28. Now what?

The first time your [phone/reader] buzzes11,28, take a breath. That sound is a cue to look, not panic. Open your [FreeStyle Libre app/reader] and glance at two things:

  1. Your current glucose number
  2. The trend arrow showing if your levels are rising or falling 

If levels are moving fast, you’ll know it’s time to take action. 

Smartphone displaying a Low Glucose Alarm notification on the lock screen with a glucose reading of 80 mg/dL.

Quick tip: Notice patterns in your alarms.

Was your alarm connected to a particular meal or lots of movement? Did you get an alarm the last time this happened, too?
 

Over time, you’ll start to see not just data, but patterns that make sense, helping you set new health goals that you can meet with the help of FreeStyle Libre system.

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