How many sensors are included in a Freestyle Libre 2 (Continuous Glucose Monitoring System) box?

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Last updated: August 13, 2025View editorial policy

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FreeStyle Libre 2 Plus Box Contains 2 Sensors

Each FreeStyle Libre 2 Plus box contains 2 sensors, with each sensor designed to be worn for 15 days, providing a total of 30 days of continuous glucose monitoring.

Sensor Specifications and Usage

The FreeStyle Libre 2 Plus system represents an evolution in continuous glucose monitoring (CGM) technology with the following key characteristics:

  • Each sensor lasts for 15 days (compared to 14 days in earlier versions) 1
  • Factory-calibrated sensors that do not require finger-stick calibration 2
  • Improved sensor design to reduce vitamin C interference 1
  • Real-time glucose data with optional alarms for high and low glucose values 2

Clinical Performance

The FreeStyle Libre 2 Plus system demonstrates excellent accuracy across different age groups:

  • 94.2% of readings within ±20 mg/dL/20% of laboratory values in adults 1
  • 94.0% of readings within ±20 mg/dL/20% of laboratory values in pediatric patients (6-17 years) 1
  • Mean Absolute Relative Difference (MARD) of 8.2% in adults and 8.1% in pediatric patients 1
  • Particularly strong performance in the hypoglycemic range, with 97-98% of results within ±15 mg/dL of laboratory values 1

Important Usage Considerations

When using the FreeStyle Libre 2 Plus system, patients should be aware of several key factors:

  • The system measures interstitial fluid glucose rather than blood glucose, which may result in differences between sensor readings and blood glucose values, particularly during rapid glucose changes 3
  • After glucose loading, FreeStyle Libre readings may be higher than actual plasma glucose concentrations 3
  • Regular scanning of the sensor is required to capture complete 24-hour data (at least every 8 hours) 2
  • Adherence to the recommended 15-day replacement schedule is crucial for maintaining optimal accuracy 4

Clinical Utility

The FreeStyle Libre system offers several advantages for diabetes management:

  • Reduces the need for painful finger-stick blood glucose tests 5
  • Associated with reduction in hypoglycemia in randomized trials 5
  • Observational studies show improvements in HbA1c levels 5
  • High user satisfaction and low adverse event rates 5
  • Lower cost compared to other real-time CGM systems 5

Potential Pitfalls

Healthcare providers and patients should be aware of these important considerations:

  1. Proper sensor placement is critical, especially in smaller patients 6
  2. Therapeutic decisions should not be made based solely on CGM readings during rapid glucose changes or suspected hypoglycemia without confirmation 2
  3. Patient education on proper interpretation of glucose data is essential for maximizing benefits 4
  4. Scanning frequency tends to decrease over time, which may impact the clinical benefits 7

The FreeStyle Libre 2 Plus system represents an important advancement in diabetes management technology, providing 30 days of continuous glucose monitoring with two 15-day sensors per box.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Diabetes Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Flash forward: a review of flash glucose monitoring.

Diabetic medicine : a journal of the British Diabetic Association, 2018

Research

Pneumothorax suspected secondary to continuous glucose monitor placement in a dog.

The Canadian veterinary journal = La revue veterinaire canadienne, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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