Reasons Freestyle Libre Sensor can only be used for 14 days

Main Reason Freestyle Libre Sensor Can Only be Used for 14 Days

Continuous Glucose Monitoring (CGM) has revolutionized the way individuals with diabetes manage their condition, providing real-time insights into blood glucose levels. Among the prominent players in the CGM market, the Freestyle Libre Sensor has gained widespread popularity.

The Freestyle Libre is a type of continuous glucose monitoring (CGM) system developed by Abbott. It is designed to help people with diabetes monitor their blood glucose levels more conveniently and continuously compared to traditional methods such as fingerstick testing.

However, users often wonder why this innovative sensor is limited to a 14-day usage period. In this article, we explore the main reasons behind the Freestyle Libre Sensor’s 14-day limitation and explore the scientific intricacies involved.

Understanding Continuous Glucose Monitoring

Before we explore the limitations of the Freestyle Libre Sensor, it is crucial to grasp the fundamentals of CGM technology. CGM devices, including the Freestyle Libre, consist of a small sensor inserted under the skin to measure glucose levels in the interstitial fluid continuously. This data is then transmitted to a receiver or smartphone, offering users real-time information about their glucose levels, trends, and patterns.

The 14-Day Limitation: Technical Constraints

One of the primary reasons behind the 14-day limitation of the Freestyle Libre Sensor lies in technical constraints related to sensor accuracy and calibration. Over time, sensors may experience a decline in accuracy due to various factors, such as tissue reaction at the insertion site, signal degradation, and changes in sensor sensitivity. Abbott, like other CGM manufacturers, establishes a 14-day usage window to ensure that users receive reliable and precise glucose readings throughout the sensor’s lifespan.

Tissue Reaction and Biocompatibility

The human body is a dynamic environment, and when a sensor is inserted beneath the skin, it interacts with the surrounding tissues. Over an extended period, tissue reactions can occur, potentially affecting the accuracy of glucose readings. The 14-day limit is a balance between obtaining meaningful data and minimizing the impact of these tissue reactions.

Sensor Calibration and Accuracy

Calibration is a critical aspect of CGM technology. During the initial phase of sensor insertion, users typically calibrate the device using fingerstick blood glucose readings. As time progresses, sensor accuracy can drift, necessitating recalibration to maintain reliability. The 14-day limit aligns with the calibration intervals recommended by manufacturers, ensuring that users consistently receive accurate glucose data.

Signal Degradation and Sensor Performance

Continuous exposure to body fluids and the physiological environment can lead to signal degradation in the sensor. Factors such as moisture, temperature variations, and biochemical interactions can impact the sensor’s performance. By limiting usage to 14 days, manufacturers mitigate the risk of signal degradation, preserving the sensor’s ability to provide reliable and timely glucose measurements.

User Safety and Regulatory Compliance

Beyond technical considerations, user safety and regulatory compliance play a pivotal role in determining the 14-day limit for the Freestyle Libre Sensor. Regulatory bodies, such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA), set guidelines for the development and approval of medical devices. Adhering to these guidelines ensures that CGM devices meet stringent safety and efficacy standards, protecting the well-being of users.

The Cost-Effectiveness Factor

While users may wish for a longer usage period for economic reasons, there are practical considerations related to cost-effectiveness. The 14-day limit strikes a balance between providing valuable continuous glucose monitoring and managing the overall cost of diabetes management for individuals and healthcare systems.


The 14-day limitation of the Freestyle Libre Sensor is a result of a careful consideration of technical, biological, and regulatory factors. By adhering to this timeframe, Abbott aims to provide users with a reliable and accurate tool for managing their diabetes while prioritizing safety and compliance with regulatory standards. As technology advances, future iterations of CGM devices may bring extended usage periods, but for now, the 14-day limit serves as a testament to the intricate balance between innovation and practicality in the realm of continuous glucose monitoring.

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