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Survive & Thrive · CGM Series

FreeStyle Libre — what it offers, how to get the most from it

Side 1 of 2
What Libre offers
Libre 3 Plus / 2 Plus
Framework score

FreeStyle Libre at a glance

5 / 5
iCGM-designated, non-adjunctive Largest UK market share. Libre 3 Plus is the smallest CGM commercially available.
Accuracy (Libre 3)
93.4%
±20/20 · pivotal
Wear
15d
Libre 3 Plus / 2 Plus
Age
4+
Libre 3 · Libre 2 all ages
Ref: Abbott 2022 pivotal · Vaughan 2025 DTT meta-analysis · 93.4% within ±20/20 · <0.1% outside ±40/40.
The essentials
15-day wear. Libre 3 Plus and 2 Plus. No grace period after 15 days.
60-minute warm-up on sensor start.
Libre 3: every 1 minute. Continuous Bluetooth push. No scanning needed.
Libre 2: scan to read. Bluetooth alarms only. Scan for current glucose.
Libre 3 is the smallest CGM - more than half the size of Libre 2. Significantly smaller than G7.
Factory calibrated. No calibrations. Finger-stick if a reading feels wrong.
FP10 prescribable in England. Largest NHS-supplied CGM.
Getting the most from Libre · Part 1

Alerts - the three that matter

  • Low glucose alert. Default 3.9 mmol/L. Tune to your floor. Bluetooth, does not require scanning.
  • High glucose alert. Set against your time-in-range goal.
  • Signal loss alert. Keep phone within Bluetooth range. If app closes, alarms stop.
Connectivity tip. LibreLink app must stay running in the background. Swiping it closed interrupts Bluetooth and you lose alerts until you reopen it.
Sharing & reporting

LibreLinkUp and LibreView

  • LibreLinkUp - real-time sharing with family, carers and HCPs. Up to 20 followers.
  • LibreView - free web-based reports for you and your team. AGP, time-in-range, hypo patterns.
  • LibreView Pro - integrates with SystmOne and EMIS. SNOMED-coded. Your GP surgery can see your data during appointments.
Getting the most from Libre · Part 2

Trend arrows - your most important signal

Libre arrows describe current rate of change. The arrow tells you what's about to happen; the number tells you what is.

ArrowRate of changeWhat it tells you
rising fast (> 2 mmol/L per 15 min)Fast rise - act now
rising (1-2 mmol/L per 15 min)Rising - consider correction or walk
stable (< 1 mmol/L per 15 min)Steady
falling (1-2 mmol/L per 15 min)Falling - check insulin on board
falling fast (> 2 mmol/L per 15 min)Pre-empt the hypo
Libre uses 5 arrows (Dexcom uses 7). Less granularity at the extremes - when you see or , assume at the top of the range and act.
AID partners

Automated insulin delivery with Libre

  • CamAPS FX (YpsoPump) - Libre 3 and 3 Plus, native.
  • Omnipod 5 - Libre 2 Plus only.
  • iLet / Twiist / Control-IQ / 780G - not Libre-compatible.
Choosing between Libre 2 Plus and Libre 3 Plus? Libre 3 Plus for CamAPS FX or smallest footprint. Libre 2 Plus for Omnipod 5.
Survive & Thrive · CGM Series

FreeStyle Libre — the 20% that makes 80% of the difference

Side 2 of 2
How to get the most out of it
Libre 3 Plus / 2 Plus
Major in the majors · #1

Skin care and sites

Libre lasts 15 days - the longest of any mainstream CGM. That makes good skin prep even more important.

  • Approved site. Back of upper arm (adults and children 4+).
  • Clean and dry. Alcohol wipe, full dry before applying.
  • Barrier wipe (Skin-Tac, Cavilon) for sensitive or sweaty skin.
  • Overlay patch for sport, swimming, warm climates. Libre's small footprint makes patches easy.
  • Rotate arms. Left one cycle, right the next.
  • Reaction? Stop and speak to your diabetes team. Abbott sensors use different adhesive chemistry to Dexcom - a common culprit is colophonium rather than IBOA.
Major in the majors · #2

Accuracy - when to trust it, when to confirm

  • First 12 hours. Can read low. If the reading doesn't match how you feel, confirm with a finger-stick.
  • Pressure (compression) lows. Lying on the sensor at night drops the reading. If you wake to a sudden after hours stable, suspect compression before treating.
  • Rapid changes. Sensor glucose lags blood glucose by ~5 minutes. The arrow is already telling you.
  • Keep the app open. Libre's biggest accuracy issue is missed data from closing the app. Background permission ON, battery optimisation OFF for LibreLink.
  • Hypo registration. A hypo must last 15+ minutes below 3.9 mmol/L to count as an event in reports. Quick treatment may not register - your felt experience is still valid.