FreeStyle Libre 2 Plus

The FreeStyle Libre 2 Plus is Abbott's 15-day successor to the original FreeStyle Libre 2, which it has replaced. It is a small, factory-calibrated continuous glucose monitor (CGM): a round sensor you wear on the back of your upper arm that measures glucose in the fluid just under your skin and sends a reading to your phone or reader every minute over Bluetooth.¹ A one-hour warm-up follows insertion, and no fingerstick calibration is needed during wear.¹

Accuracy. In the pivotal study of the 15-day sensor (shared with the Libre 3 Plus), overall MARD — the average gap between sensor and lab glucose, where lower is better — was 8.2% in adults and 8.1% in children aged 6–17, with about 94% of readings within 20%/20 mg/dL of the lab reference.² That is a modest improvement on the original Libre 2's ~9.2% MARD.³ Crucially for safety, it held up in the low range: 97–98% of results were within 15 mg/dL of the lab value during hypoglycemia.² In the youngest children (2–5 years), accuracy was lower (11.2% MARD against fingerstick comparison).²

Alerts. Glucose alarms are optional and configurable — you can switch on high, low, urgent-low, and signal-loss alerts and set your own thresholds, or run without them.¹ Unlike some rivals, it alerts on your current level rather than offering true predictive (ahead-of-time) alarms.

What it works with. The Libre 2 Plus is an "integrated CGM" (iCGM) cleared to drive automated insulin delivery (AID) systems.⁴ It powers the Tandem t:slim X2 with Control-IQ technology (integrated January 2024)⁵ and the tubeless Omnipod 5 (added November 2024 in the US).⁶ It runs from the single FreeStyle Libre app on supported phones, or a dedicated reader.¹ For DIY loops (AndroidAPS, etc.), there is no official support: data must be bridged through third-party apps such as xDrip+ or Juggluco, and direct connection works only with EU sensor models — a real limitation versus more loop-friendly sensors.⁷

Ketones. This sensor measures glucose only; it has no ketone sensing. Abbott is separately developing a dual glucose-ketone sensor (later branded Libre Duo), built on the smaller Libre 3 form factor — tracked elsewhere on this site.⁸

Who it's for. It is indicated for adults and children aged 2 and older, including in pregnancy, and is worn on the back of the upper arm.⁴

Access & cost. This is Abbott's lower-cost tier, widely available across the US, UK, Europe, Canada, Australia, and Japan, and reimbursed by many health systems — in the UK it is available on the NHS to those who meet NICE criteria.⁹ Where paid out of pocket in the US, the roughly monthly supply of two sensors carries a meaningful cash cost without insurance, though insurance, discount cards, and pharmacy benefit programs usually lower this substantially.¹⁰

What's coming. Abbott is steering users toward the even-smaller Libre 3 line, but the bigger leap is the dual glucose-ketone sensor: it streams glucose and ketones each minute (ketones being the early-warning signal for diabetic ketoacidosis) and has CE-mark approval in Europe, with several pump makers announcing integration plans.⁸ Expect future AID systems to fold that capability in.

References

1. Abbott. FreeStyle Libre 2 Plus — Continuous Glucose Monitoring (provider specifications: 15-day wear, 1-hour warm-up, minute updates, optional alarms, age 2+). FreeStyle Libre Providers (2025). https://www.freestyleprovider.abbott/us-en/freestyle-libre-2.html ↩ ↩² ↩³ ↩⁴

2. Alva S, Bhargava A, Bode B, et al. Accuracy of a 15-day Factory-Calibrated Continuous Glucose Monitoring System With Improved Sensor Design. J Diabetes Sci Technol (2025). doi:10.1177/19322968251329364 (PMID 40183340). https://pmc.ncbi.nlm.nih.gov/articles/PMC11977615/ ↩ ↩² ↩³

3. Abbott. FreeStyle Libre 2 System: Accuracy is Everything (overall 9.2% MARD for the original Libre 2). Abbott Newsroom. https://www.abbott.com/en-us/corpnewsroom/strategy-and-strength/freestyle-libre-2-system-accuracy-is-everything ↩

4. Abbott. U.S. FDA Clears Abbott's FreeStyle Libre 2 and FreeStyle Libre 3 Sensors for Integration with Automated Insulin Delivery Systems (iCGM; 15-day modified sensors; age 2+; pregnancy). Abbott Newsroom (March 6, 2023). https://abbott.mediaroom.com/2023-03-06-U-S-FDA-Clears-Abbotts-FreeStyle-Libre-R-2-and-FreeStyle-Libre-R-3-Sensors-for-Integration-with-Automated-Insulin-Delivery-Systems ↩ ↩²

5. Abbott / Tandem Diabetes Care. Tandem's t:slim X2 Insulin Pump is the First AID System to Integrate with Abbott's New FreeStyle Libre 2 Plus Sensor (Control-IQ; minute updates; 15-day wear). Abbott Newsroom (January 8, 2024). https://abbott.mediaroom.com/2024-01-08-Tandem-Diabetes-Cares-t-slim-X2-Insulin-Pump-is-the-First-Automated-Insulin-Delivery-System-to-Integrate-with-Abbotts-New-FreeStyle-Libre-2-Plus-Sensor ↩

6. Beyond Type 1. Insulet Adds FreeStyle Libre 2 Plus to Omnipod 5 Compatibility (US, November 21, 2024; SmartAdjust every 5 minutes). Beyond Type 1 (2024). https://beyondtype1.org/insulet-adds-freestyle-libre-2-plus-to-omnipod-5-compatibility/ ↩

7. AndroidAPS. FreeStyle Libre 2 and 2+ — Compatible CGMs (no native Bluetooth; bridge via xDrip+/OOP2/Juggluco; direct connection EU models only). AndroidAPS documentation (2024). https://androidaps.readthedocs.io/en/latest/CompatibleCgms/Libre2.html ↩

8. Abbott. Abbott Announces Development of Novel Continuous Glucose-Ketone Monitoring System (dual glucose-ketone sensor on Libre 3 form factor; minute readings). PR Newswire / Abbott (2022). https://www.prnewswire.com/news-releases/abbott-announces-development-of-novel-continuous-glucose-ketone-monitoring-system-301560808.html ↩ ↩²

9. Abbott. Cost & Coverage — FreeStyle Libre (UK NHS availability via NICE criteria). FreeStyle Libre UK (2025). https://www.freestyle.abbott/uk-en/getting-started/costandcoverage.html ↩

10. SingleCare. How much is a FreeStyle Libre 2 Sensor without insurance? (US cash-pay context for the uninsured). SingleCare (2024). https://www.singlecare.com/blog/freestyle-libre-2-sensor-without-insurance/ ↩