← Product Code [QLG](/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/QLG) · K211102

# FreeStyle Libre 2 Flash Glucose Monitoring System (K211102)

_Abbott Diabetes Care, Inc. · QLG · Aug 11, 2021 · Clinical Chemistry · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/QLG/K211102

## Device Facts

- **Applicant:** Abbott Diabetes Care, Inc.
- **Product Code:** [QLG](/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/QLG.md)
- **Decision Date:** Aug 11, 2021
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 862.1355
- **Device Class:** Class 2
- **Review Panel:** Clinical Chemistry
- **Attributes:** Pediatric

## Indications for Use

The FreeStyle Libre 2 Flash Glucose Monitoring System is a continuous glucose monitoring (CGM) device with real time alarms capability indicated for the management of diabetes in persons age 4 and older. It is intended to replace blood glucose testing for diabetes treatment decisions, unless otherwise indicated. The System also detects trends and tracks patterns and aids in the detection of episodes of hyperglycemia and hypoglycemia, facilitating both acute and long-term therapy adjustments. Interpretation of the System readings should be based on the glucose trends and several sequential readings over time. The System is also intended to autonomously communicate with digitally connected devices. The System can be used alone or in conjunction with these digitally connected devices where the user manually controls actions for therapy decisions. The System can be used with the FreeStyle Libre 2 Sensor (14 day) or the FreeStyle Libre 2 MediRx Sensor (10 day).

## Device Story

System monitors interstitial fluid glucose via subcutaneously implanted electrochemical sensor; glucose oxidase enzyme oxidizes glucose to produce current proportional to concentration. Sensor transmits data via Bluetooth Low Energy (BLE) and RFID to handheld Reader. Reader displays real-time glucose values, trends, and history; provides configurable alarms for high/low glucose or signal loss. Used at home by patients; requires prescription. Reader includes built-in blood glucose test strip port. Subject device adds compatibility with 10-day wear sensor (MediRx) alongside existing 14-day sensor. Reader automatically detects sensor type via manufacturing-set configuration parameter to adjust wear-time display and shut-off timing. Output aids patients in diabetes treatment decisions and therapy adjustments.

## Clinical Evidence

Two prospective clinical studies (adults and pediatric) evaluated accuracy against YSI 2300 laboratory comparator. Data reanalyzed for 10-day wear. Adult MARD 9.9% (beginning) to 9.0% (end). Pediatric MARD 10.7% (beginning) to 9.8% (end). Concurrence analysis and alarm performance (True/False/Detection rates) provided. Sensor survival rate 82.2% (adult) and 89.9% (pediatric) at 10 days; 100% survival achieved in study following strict site preparation instructions.

## Technological Characteristics

Amperometric electrochemical sensor using glucose oxidase. Sensor powered by silver oxide battery; Reader powered by lithium-ion rechargeable battery. Connectivity via NFC (13.56 MHz) and BLE 4.0 (20 ft range). Sensor dimensions: 5.5 mm tail insertion depth. Sterilization: Electron beam. Software: Factory-calibrated, rule-based algorithm for glucose calculation and wear-time management.

## Regulatory Identification

An integrated continuous glucose monitoring system (iCGM) is intended to automatically measure glucose in bodily fluids continuously or frequently for a specified period of time. iCGM systems are designed to reliably and securely transmit glucose measurement data to digitally connected devices, including automated insulin dosing systems, and are intended to be used alone or in conjunction with these digitally connected medical devices for the purpose of managing a disease or condition related to glycemic control.

## Special Controls

*Classification.* Class II (special controls). The special controls for this device are:(1) Design verification and validation must include the following:
(i) Robust clinical data demonstrating the accuracy of the device in the intended use population.
(ii) The clinical data must include a comparison between iCGM values and blood glucose values in specimens collected in parallel that are measured on an FDA-accepted laboratory-based glucose measurement method that is precise and accurate, and that is traceable to a higher order (
*e.g.,* an internationally recognized reference material and/or method).(iii) The clinical data must be obtained from a clinical study designed to fully represent the performance of the device throughout the intended use population and throughout the measuring range of the device.
(iv) Clinical study results must demonstrate consistent analytical and clinical performance throughout the sensor wear period.
(v) Clinical study results in the adult population must meet the following performance requirements:
(A) For all iCGM measurements less than 70 milligrams/deciliter (mg/dL), the percentage of iCGM measurements within ±15 mg/dL of the corresponding blood glucose value must be calculated, and the lower one-sided 95 percent confidence bound must exceed 85 percent.
(B) For all iCGM measurements from 70 mg/dL to 180 mg/dL, the percentage of iCGM measurements within ±15 percent of the corresponding blood glucose value must be calculated, and the lower one-sided 95 percent confidence bound must exceed 70 percent.
(C) For all iCGM measurements greater than 180 mg/dL, the percentage of iCGM measurements within ±15 percent of the corresponding blood glucose value must be calculated, and the lower one-sided 95 percent confidence bound must exceed 80 percent.
(D) For all iCGM measurements less than 70 mg/dL, the percentage of iCGM measurements within ±40 mg/dL of the corresponding blood glucose value must be calculated, and the lower one-sided 95 percent confidence bound must exceed 98 percent.
(E) For all iCGM measurements from 70 mg/dL to 180 mg/dL, the percentage of iCGM measurements within ±40 percent of the corresponding blood glucose value must be calculated, and the lower one-sided 95 percent confidence bound must exceed 99 percent.
(F) For all iCGM measurements greater than180 mg/dL, the percentage of iCGM measurements within ±40 percent of the corresponding blood glucose value must be calculated, and the lower one-sided 95 percent confidence bound must exceed 99 percent.
(G) Throughout the device measuring range, the percentage of iCGM measurements within ±20 percent of the corresponding blood glucose value must be calculated, and the lower one-sided 95 percent confidence bound must exceed 87 percent.
(H) When iCGM values are less than 70 mg/dL, no corresponding blood glucose value shall read above 180 mg/dL.
(I) When iCGM values are greater than 180 mg/dL, no corresponding blood glucose value shall read less than 70 mg/dL.
(J) There shall be no more than 1 percent of iCGM measurements that indicate a positive glucose rate of change greater than 1 mg/dL per minute (/min) when the corresponding true negative glucose rate of change is less than −2 mg/dL/min as determined by the corresponding blood glucose measurements.
(K) There shall be no more than 1 percent of iCGM measurements that indicate a negative glucose rate of change less than −1 mg/dL/min when the corresponding true positive glucose rate of change is greater than 2 mg/dL/min as determined by the corresponding blood glucose measurements.
(vi) Data demonstrating similar accuracy and rate of change performance of the iCGM in the pediatric population as compared to that in the adult population, or alternatively a clinical and/or technical justification for why pediatric data are not needed, must be provided and determined by FDA to be acceptable and appropriate.
(vii) Data must demonstrate that throughout the claimed sensor life, the device does not allow clinically significant gaps in sensor data availability that would prevent any digitally connected devices from achieving their intended use.
(2) Design verification and validation must include a detailed strategy to ensure secure and reliable means of iCGM data transmission to provide real-time glucose readings at clinically meaningful time intervals to devices intended to receive the iCGM glucose data.
(3) Design verification and validation must include adequate controls established during manufacturing and at product release to ensure the released product meets the performance specifications as defined in paragraphs (b)(1) and (b)(2) of this section.
(4) The device must demonstrate clinically acceptable performance in the presence of clinically relevant levels of potential interfering substances that are reasonably present in the intended use population, including but not limited to endogenous substances and metabolites, foods, dietary supplements, and medications.
(5) The device must include appropriate measures to ensure that disposable sensors cannot be used beyond its claimed sensor wear period.
(6) Design verification and validation must include results obtained through a usability study that demonstrates that the intended user can use the device safely and obtain the expected glucose measurement accuracy.
(7) The labeling required under § 809.10(b) of this chapter must include a separate description of the following sensor performance data observed in the clinical study performed in conformance with paragraph (b)(1) of this section for each intended use population, in addition to separate sensor performance data for each different iCGM insertion or use sites (
*e.g.,* abdomen, arm, buttock):(i) A description of the accuracy in the following blood glucose concentration ranges: less than 54 mg/dL, 54 mg/dL to less than 70 mg/dL, 70 to 180 mg/dL, greater than 180 to 250 mg/dL, and greater than 250 mg/dL.
(ii) A description of the accuracy of positive and negative rate of change data.
(iii) A description of the frequency and duration of gaps in sensor data.
(iv) A description of the true, false, missed, and correct alert rates and a description of the available glucose concentration alert settings, if applicable.
(v) A description of the observed duration of iCGM life for the device.

## Predicate Devices

- FreeStyle Libre 2 Flash Glucose Monitoring System ([K193371](/device/K193371.md))

## Reference Devices

- FreeStyle Precision Neo Blood Glucose test strips ([K171941](/device/K171941.md))

## Submission Summary (Full Text)

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FDA U.S. FOOD & DRUG ADMINISTRATION

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

ASSAY AND INSTRUMENT

## I Background Information:

A 510(k) Number

K211102

B Applicant

Abbott Diabetes Care, Inc.

C Proprietary and Established Names

FreeStyle Libre 2 Flash Glucose Monitoring System

D Regulatory Information

|  Product Code(s) | Classification | Regulation Section | Panel  |
| --- | --- | --- | --- |
|  QLG | Class II | 21 CFR 862.1355 - Integrated Continuous Glucose Monitoring System | CH - Clinical Chemistry  |
|  NBW | Class II | 21 CFR 862.1345 - Glucose test system | CH - Clinical Chemistry  |

## II Submission/Device Overview:

A Purpose for Submission:

Modification of the cleared device to add compatibility with the 10-day MediRx sensor.

B Measurand:

Glucose in interstitial fluid

C Type of Test:

Quantitative, amperometric assay (Glucose Oxidase)

Food and Drug Administration

10903 New Hampshire Avenue

Silver Spring, MD 20993-0002

www.fda.gov

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K211102 - Page 2 of 21

# III Intended Use/Indications for Use:

## A Intended Use(s):

See Indications for Use below.

## B Indication(s) for Use:

The FreeStyle Libre 2 Flash Glucose Monitoring System is a continuous glucose monitoring (CGM) device with real time alarms capability indicated for the management of diabetes in persons age 4 and older. It is intended to replace blood glucose testing for diabetes treatment decisions, unless otherwise indicated.

The System also detects trends and tracks patterns and aids in the detection of episodes of hyperglycemia and hypoglycemia, facilitating both acute and long-term therapy adjustments. Interpretation of the System readings should be based on the glucose trends and several sequential readings over time.

The System is also intended to autonomously communicate with digitally connected devices. The System can be used alone or in conjunction with these digitally connected devices where the user manually controls actions for therapy decisions.

The System can be used with the FreeStyle Libre 2 Sensor (14 day) or the FreeStyle Libre 2 MediRx Sensor (10 day).

## C Special Conditions for Use Statement(s):

Rx - For Prescription Use Only

The System must not be used with automated insulin dosing (AID) systems, including closed loop, hybrid closed loop, and insulin suspend systems.

Taking ascorbic Acid (Vitamin C) supplements while wearing the Sensor may falsely raise Sensor glucose readings. Inaccurate sensor readings due to ascorbic acid interference may be clinical significant and result in harm if relied on to make treatment decisions. Taking more than 500 mg of ascorbic acid per day may affect the Sensor readings which could cause you to miss a severe low glucose event.

The System must be removed prior to Magnetic Resonance Imaging (MRI), Computed Tomography (CT) scan, or high-frequency electrical heat (diathermy) treatment. The effect of MRI, CT scans, or diathermy on the performance of the System has not been evaluated. The exposure may damage the Sensor and may impact proper function of the device which could cause incorrect readings.

Do not use this system if you are pregnant, on dialysis, or critically ill. The System is not cleared for use in these groups and it is not known how different conditions or medications common to these populations may affect performance of the System.

Do not ignore symptoms that may be due to low or high blood glucose: if you are experiencing symptoms that are not consistent with the glucose readings, consult your health care professional.

Do not use the System in people less than 4 years of age.

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Use your blood glucose meter to make diabetes treatment decisions when you see the "check blood glucose" symbol during the first 12 hours or wearing a Sensor. In addition, use your blood glucose meter to make diabetes treatment decisions, if your Sensor glucose reading does not match how you feel, or if the reading does not include a number.

Wash application site on the back of your upper arm using a plain soap, dry, and then clean with an alcohol wipe. This will help remove any oily residue that may prevent the sensor from sticking properly. Allow site to air dry before proceeding. Carefully preparing the site according to these instructions will help the Sensor stay on your body for the full 14-day wear period and help prevent it from falling off early.

Store the Sensor Kit between 36°F and 82°F. If you suspect that the temperature may exceed 82°F (e.g., an un-airconditioned home in the summer), you should refrigerate your Sensor Kit. Do not freeze your Sensor Kit.

You must scan the Sensor to get your real-time current glucose level as the Reader will not provide this information without a scan.

The Reader's built-in meter is not for use on people who are dehydrated, hypotensive, in shock, or for individuals in hyperglycemic-hyperosmolar state, with or without ketosis.

The Reader's built-in meter is not for use on neonates, in critically-ill patients, or for diagnosis or screening of diabetes.

Take standard precautions for transmission of blood borne pathogens to avoid contamination.

Use of the Sensor with devices, apps, and software that are not listed by the manufacturer as compatible with the System may cause inaccurate glucose readings.

If a Sensor breaks inside a user's body, they should call their health care professional.

## D Special Instrument Requirements:
Not applicable.

## IV Device/System Characteristics:

### A Device Description:

The FreeStyle Libre 2 Flash Glucose Monitoring System is an integrated continuous glucose monitoring (iCGM) system that provides continuous glucose measurements every minute to provide glucose levels, trends, and real-time alarms capability to aid in the management of diabetes. The FreeStyle Libre 2 System consists of two primary components: a Sensor that transmits via Bluetooth Low Energy (BLE), and a BLE enabled display device (Reader). User initiated radiofrequency identification (RFID) scanning of the Sensor via Reader provides the user with real-time glucose measurements (glucose values) accompanied by trend information (glucose arrows) and historical glucose information (glucose graph). Users may use the Sensor glucose results and information provided by the System in making treatment decisions. The System also provides configurable alarms designed to warn the user of Low Glucose, High

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Glucose or Signal Loss. The system is intended for single-patient use at home and requires a prescription.

## FreeStyle Libre 2 Sensor

- The Sensor is single use and disposable. The Sensor is provided as two secondary components, Sensor Applicator and Sensor Pack (sterile device), which are used to assemble and apply the Sensor to the back of the user's arm. During Sensor application, the sensor tail is inserted below the surface of the skin through the guidance of a needle. The needle is retracted back into the applicator after insertion. The Sensor continuously measures glucose concentration in interstitial fluid every minute and has an 8-hour memory capacity. The Sensor is factory calibrated and does not require fingerstick calibration.

## FreeStyle Libre 2 Reader

- The Reader is a small handheld device that is powered by a lithium-ion rechargeable battery and uses RFID communication to start new Sensors and to scan Sensors to display and record data and uses blue tooth low energy BLE communication to issue alarms that notify the user to scan his/her sensor when glucose values pass a high or low glucose threshold. The Reader also has a built-in strip port with blood glucose functionality (that is intended to work with the FreeStyle Precision Neo Blood Glucose test strips, cleared under K171941), and a user interface that includes event logging features.

The FreeStyle Libre 2 MediRx Sensor with a 10-day wear duration is an alternate configuration to the existing FreeStyle Libre 2 Sensor, which has a 14-day wear duration. The FreeStyle Libre 2 MediRx Sensor design is unchanged from that of the predicate Sensor (the FreeStyle Libre 2 Flash Glucose Monitoring System). The algorithm and Reader design in the FreeStyle Libre 2 MediRx Sensor are also the same as those of the predicate.

As with the predicate, the System is intended to be used when the user utilizes CGM information to manually control actions for therapy decisions. The System must not be used with automated insulin dosing (AID) systems, which include full closed loop, hybrid closed loop, and insulin suspend (e.g., threshold suspend and predictive low glucose suspend) systems.

## B Principle of Operation:

The FreeStyle Libre 2 Flash Glucose Monitoring System uses an electrochemical sensor to monitor glucose levels in the interstitial fluid (ISF). The sensor is held in place with an adhesive pad and incorporates both the subcutaneously implanted sensor and associated electronics. The sensor uses a glucose oxidase enzyme to oxidize glucose and transfer electrons to a metal electrode, producing a current. The strength of the current is proportional to the amount of glucose present in the subcutaneous space. The FreeStyle Libre 2 System converts the electrical current signal to a glucose value (in mg/dL) for display to the user on the handheld Reader.

## C Instrument Description Information:

1. Instrument Name: FreeStyle Libre 2 Flash Glucose Monitoring System

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2. Specimen Identification:
Not applicable.

3. Specimen Sampling and Handling:
Not applicable.

4. Calibration:
The device is factory calibrated and does not require calibration from the user/operator.

5. Quality Control:
Not applicable.

V Substantial Equivalence Information:

A Predicate Device Name(s):
FreeStyle Libre 2 Flash Glucose Monitoring System

B Predicate 510(k) Number(s):
K193371

C Comparison with Predicate(s):

|  Device & Predicate Device(s): | K211102 | K193371  |
| --- | --- | --- |
|  Device Trade Name | FreeStyle Libre 2 Flash Glucose Monitoring System | FreeStyle Libre 2 Flash Glucose Monitoring System  |
|  General Device Characteristic Similarities |  |   |
|  Intended Use/Indications For Use | The FreeStyle Libre 2 Flash Glucose Monitoring System is a continuous glucose monitoring (CGM) device with real-time alarm capability indicated for the management of diabetes in persons age 4 and older. It is intended to replace blood glucose (BG) testing for diabetes treatment decisions unless otherwise indicated.
The System also detects trends and tracks patterns and aids in the detection of episodes of hyperglycemia and hypoglycemia, facilitating both acute and long-term therapy adjustments. Interpretation of the System readings should be | Same  |

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K211102 - Page 6 of 21
|  Device & Predicate Device(s): | K211102 | K193371  |
| --- | --- | --- |
|   | based on the glucose trends and several sequential readings over time.

The System is also intended to autonomously communicate with digitally connected devices. The System can be used alone or in conjunction with these digitally connected devices where the user manually controls actions for therapy decisions. |   |
|  Device Type | Integrated CGM | Same  |
|  Principle of Operation | Amperometric measurement of current proportional to glucose concentration in interstitial fluid via glucose oxidase chemical reaction | Same  |
|  Test Range | 40 to 400 mg/dL | Same  |
|  Clinical Setting/Sites of Use | Home Setting | Same  |
|  Data Displayed | Current glucose value, current glucose trend, graph with recent glucose history, user-entered events | Same  |
|  Primary Display Device | FreeStyle Libre 2 Reader | Same  |
|  Alerts and Alarms | Low Glucose Alarm, High Glucose Alarm, Signal Loss Alarm, Scan Error, Sensor Error | Same  |
|  Wireless Communication Protocol | Near Field Communication (NFC): (13.56 MHz RFID) Bluetooth Low Energy (BLE): 4.0 | Same  |
|  BLE Communication | 20 feet unobstructed | Same  |
|  Sensor Glucose Algorithm | FreeStyle Libre 2 Reader Algorithm | Same  |
|  Method of Sensor Activation | RFID Communication | Same  |
|  Method of Data Transfer from Sensor | RFID – upon user-initiated scan BLE – for glucose data to support glucose alarms | Same  |
|  Glucose Reading Update Interval | Every 1 minute | Same  |

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|  Device & Predicate Device(s): | K211102 | K193371  |
| --- | --- | --- |
|  Trend Graph Glucose History | 8 hours, 24-hour graph and other reports can be used to view logged data | Same  |
|  Sensor Calibration | Factory calibrated | Same  |
|  Anatomical Sensor Wear Locations | Back of upper arm | Same  |
|  Sensor Warm-up Time | 1 hour | Same  |
|  General Device Characteristic Differences |  |   |
|  Compatible Sensors | FreeStyle Libre 2 Sensor (14-day), or FreeStyle Libre 2 MediRx Sensor (10-day) | FreeStyle Libre 2 Sensor (14-day)  |
|  Retail Packaging Configuration for FreeStyle Libre 2 MediRx Sensor Kits | Two (2) packaging configuration options:
• One (1) Sensor Kit carton with no additional outer carton
• Three (3) individual Sensor Kit cartons packaged within an outer carton | N/A  |

VI Standards/Guidance Documents Referenced:

- FDA Guidance document Applying Human Factors and Usability Engineering to Medical Devices (February 3, 2016)
- ISO 14971: 2019 – “Medical Devices-Application of Risk Management to Medical Devices”
- ANSI AAMI IEC 62304:2006/A1:2016 - “Medical device software - Software life cycle processes”
- AAMI/IEC 62366-1:2015 - “Medical Devices-Application of Usability Engineering to Medical Devices”
- AAMI/ANSI HE75: 2009/(R)2018 - “Human Factors Engineering -Design of Medical Devices”

VII Performance Characteristics (if/when applicable):

A Analytical Performance:

1. Precision/Reproducibility:

Precision of the System with the FreeStyle Libre 2 sensor (14 day) was previously established in K193371. Precision data was reanalyzed for the proposed 10-day wear period of the FreeStyle Libre 2 MediRx sensor and presented in the tables below.

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For adults (18 years and older), the paired absolute relative difference (PARD) between the two sensors was 8.2% with mean coefficient of variation (CV) of 5.8%. For children ages 4-5, PARD was 6.9% with mean CV of 4.9%. For children ages 6-17, PARD was 8.0% with CV of 5.7%.

Overall between Sensor Precision (Adult; n=146)

|   | Mean Coefficient of Variation (%) | Paired Absolute Difference (mg/dL) | Paired Absolute Relative Difference (%) | Number of Paired Readings  |
| --- | --- | --- | --- | --- |
|  Adults ages 18+ | 5.8 | 12.6 | 8.2 | 20524  |

Overall between Sensor Precision (Pediatric; n=137)

|   | Mean Coefficient of Variation (%) | Paired Absolute Difference (mg/dL) | Paired Absolute Relative Difference (%) | Number of Paired Readings  |
| --- | --- | --- | --- | --- |
|  Children ages 4-5 | 4.9 | 11.0 | 6.9 | 209  |
|  Children ages 6-17 | 5.7 | 12.8 | 8.0 | 7797  |

2. Linearity:
See Section A(4), Assay Reportable Range below

3. Analytical Specificity/Interference:
For this device and the predicate, ascorbic acid (vitamin C) has been shown to significantly interfere with system performance. Analytical Specificity/Interference was previously assessed in K193371.

Based on the results of the clinical evaluation and bench testing for ascorbic acid, the following statements have been placed in the device labeling:

- User Manual Warning: Taking ascorbic acid (vitamin C) supplements while wearing the Sensor may falsely raise Sensor glucose readings. Taking more than 500 mg of ascorbic acid per day may affect the Sensor readings which could cause you to miss a severe low glucose event. Ascorbic acid can be found in supplements including multivitamins. Some supplements, including cold remedies such as Airborne® and Emergen-C®, may contain high doses of 1000 mg of ascorbic acid and should not be taken while using the Sensor. See your healthcare professional to understand how long ascorbic acid is active in your body.
- Reader Screen Warning: Do not take high doses of vitamin C (more than 500 mg per day). This may falsely raise your Sensor readings. Supplements like Airborne or Emergen-C have high doses of vitamin C. Read labeling for all supplements to determine vitamin C content.

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4. Assay Reportable Range:
The Assay Reportable Range was previously assessed in K193371. The reportable range for the System with the FreeStyle Libre 2 MediRx Sensor remains unchanged as 40 to 400 mg/dL.

5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
The shelf-life of the FreeStyle Libre 2 sensor was previously evaluated in K193371. Both the FreeStyle Libre 2 sensor and FreeStyle Libre 2 MediRx sensor have a storage shelf life of 9 months. Shelf-life was evaluated at 36° - 82° Fahrenheit within the humidity range of 10% - 90%.

6. Detection Limit:
If a glucose measurement is less than 40 mg/dL, the result will be displayed by the system as 'LO'. If the glucose measurement exceeds 400 mg/dL, the result will be displayed as 'HI'.

7. Assay Cut-Off:
Not applicable.

8. Accuracy (Instrument):
Not applicable.

9. Carry-Over:
Not applicable.

B Comparison Studies:

1. Method Comparison with Predicate Device:
Not applicable. Accuracy is determined by comparing device values to an FDA-cleared laboratory glucose measurement method and was previously assessed in K193371.

2. Matrix Comparison:
Not applicable. Interstitial fluid is the only indicated matrix.

C Clinical Studies:

1. Clinical Sensitivity:
Not applicable.

2. Clinical Specificity:
See Section A(3), Analytical Specificity/Interference, above.

3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):
Two prospective clinical studies were conducted in the United States to support clearance of the predicate device in K193371.

In both studies, accuracy of the FreeStyle Libre 2 sensor was evaluated by comparing iCGM glucose values to an FDA-cleared laboratory grade comparator method (CM, using the YSI 2300). Glucose values were obtained from the iCGM and from the comparator at the same or similar time. The accuracy of iCGM glucose versus the comparator method was assessed by

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calculating the percentage of iCGM readings that were within 15%, 20%, and 40% for reference values ≥70 mg/dL, and within 15 mg/dL, 20 mg/dL, and 40 mg/dL for values < 70 mg/dL. For glucose values < 70 mg/dL, the difference in mg/dL between the CGM and comparator glucose values was calculated. For values ≥70 mg/dL, the relative difference (%) to the comparator value was calculated.

The study data was reanalyzed to include data from the first 10 days of sensor wear, to align with the proposed intended use of the System with the FreeStyle Libre 2 MediRx Sensor. The sponsor did not collect paired glucose data on Day 10 due to the clinic visit schedule for both studies. Therefore, paired CGM-CM data up to Day 9 are presented in the tables below. Assessment of Day 12 data (where paired CGM-CM data are available) indicates that the performance data below is representative of the device performance for 10 days of wear.

Percent and Point Accuracy by iCGM Glucose Range (Adult)

|  iCGM Glucose Range (mg/dL) | No. Pairs | Percent within 15 mg/dL (95% LCL*) | Percent within 40 mg/dL (95% LCL) | Percent within 15% (95% LCL) | Percent within 40% (95% LCL) | Mean Bias, mg/dL (95% UCL*)  |
| --- | --- | --- | --- | --- | --- | --- |
|  <70 | 2550 | 88.1 (85.9) | 99.2 (98.8) |  |  | -4.0 (-3.0)  |
|  70-180 | 5340 |  |  | 75.9 (72.9) | 99.6 (99.4) | -6.7 (-5.0)  |
|  >180 | 5444 |  |  | 92.2 (90.3) | 99.9 (99.9) | -5.7 (-3.2)  |

*95% LCL is the lower bound of the 95% confidence limit and 95% UCL is the upper bound of the 95% confidence limit

Percent and Point Accuracy by iCGM Glucose Range (Pediatric*)

|  iCGM Glucose Range (mg/dL) | No. Pairs | Percent within 15 mg/dL (95% LCL) | Percent within 40 mg/dL (95% LCL) | Percent within 15% (95% LCL) | Percent within 40% (95% LCL) | Mean Bias, mg/dL (95% UCL)  |
| --- | --- | --- | --- | --- | --- | --- |
|  <70 | 689 | 83.3 (77.6) | 98.4 (96.9) |  |  | -6.6 (-4.2)  |
|  70-180 | 1721 |  |  | 77.6 (74.2) | 99.4 (98.9) | -4.4 (-2.1)  |
|  >180 | 1949 |  |  | 90.6 (88.0) | 99.7 (99.3) | -1.9 (1.5)  |

*Includes children 6-17 years of age. No comparator measurements were obtained for children 4-5 years of age

Percent and Point Accuracy by Comparator Glucose Range (Adult)

|  CM Glucose Range (mg/dL) | No. Pairs | Percent within 15 mg/dL (95% LCL) | Percent within 40 mg/dL (95% LCL) | Percent within 15% (95% LCL) | Percent within 40% (95% LCL) | Mean Bias, mg/dL (95% UCL)  |
| --- | --- | --- | --- | --- | --- | --- |
|  <70 | 2344 | 94.6 (92.7) | 100.0 (100.0) |  |  | 0.6 (1.5)  |
|  70-180 | 5295 |  |  | 76.4 (73.6) | 99.5 (99.3) | -5.3 (-3.9)  |
|  >180 | 5695 |  |  | 89.7 (87.5) | 99.9 (99.8) | -8.1 (-5.5)  |

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Percent and Point Accuracy by Comparator Glucose Range (Pediatric*)

|  CM Glucose Range (mg/dL) | No. Pairs | Percent within 15 mg/dL (95% LCL) | Percent within 40 mg/dL (95% LCL) | Percent within 15% (95% LCL) | Percent within 40% (95% LCL) | Mean Bias, mg/dL (95% UCL)  |
| --- | --- | --- | --- | --- | --- | --- |
|  <70 | 553 | 96.0 (93.4) | 100.0 (100.0) |  |  | 1.1 (2.3)  |
|  70-180 | 1821 |  |  | 74.0 (70.3) | 99.0 (98.4) | -2.8 (-1.0)  |
|  >180 | 1985 |  |  | 89.9 (87.1) | 99.4 (98.4) | -5.0 (-1.3)  |

*Includes children 6-17 years of age. No comparator measurements were obtained for children 4-5 years of age

Percent of iCGM values within 20% of Comparator Glucose Values

|  iCGM Glucose Range (mg/dL) | No. Pairs | No. Subject | Percent within 20% (95% LCL)  |
| --- | --- | --- | --- |
|  Adult (18 years and up) | 13334 | 144 | 90.2 (88.7)  |
|  Pediatric (6-17 years) | 4359 | 106 | 90.5 (88.2)  |
|  Pediatric (4-5 years old)* | 267 | 8 | 83.5 (78.1)  |

*Subjects 4-5 years old were compared to an SMBG meter

Percent values within 15%/15 mg/dL, 20%/20 mg/dL and 40%/40 mg/dL stratified by glucose ranges of &lt;54, 54-69, 70-180. 181-250 and &gt;250 mg/dL for iCGM and laboratory comparator were also provided. For pediatric subjects ages 4-5, values were compared to SMBG

Accuracy to Comparator within iCGM Glucose Range (Adults)

|  iCGM Glucose Level †(mg/dL) | Number of CGM-Reference Pairs | Percent Within ±15 mg/dL | Percent Within ±20 mg/dL | Percent Within ±40 mg/dL | Percent Within ±15% | Percent Within ±20% | Percent Within ±40% | Mean bias (mg/dL) | MARD (%)  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  <54 | 411 | 84.7 | 93.2 | 99.3 |  |  |  | -6.6 | 13.8  |
|  54-69 | 2139 | 88.7 | 93.6 | 98.8 |  |  |  | -4.4 | 11.1  |
|  70-180 | 5340 |  |  |  | 75.9 | 86.4 | 99.1 | -5.9 | 10.8  |
|  181-250 | 2202 |  |  |  | 88.8 | 94.7 | 99.9 | -9.9 | 7.8  |
|  >250 | 3242 |  |  |  | 94.4 | 98.1 | 100.0 | -4.9 | 6.1  |

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Accuracy to Comparator within iCGM Glucose Ranges (Pediatric)

|  iCGM Glucose Level (mg/dL) | Number of CGM-Reference Pairs | Percent Within ±15 mg/dL | Percent Within ±20 mg/dL | Percent Within ±40 mg/dL | Percent Within ±15% | Percent Within ±20% | Percent Within ±40% | Mean bias (mg/dL) | MARD (%)  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  <54 | 109 | 71.6 | 77.1 | 96.3 |  |  |  | -9.7 | 17.0  |
|  54-69 | 580 | 85.5 | 89.3 | 96.2 |  |  |  | -5.8 | 11.7  |
|  70-180 | 1721 |  |  |  | 77.6 | 87.6 | 98.6 | -4.7 | 10.6  |
|  181-250 | 787 |  |  |  | 86.0 | 93.6 | 99.5 | -7.1 | 8.1  |
|  >250 | 1162 |  |  |  | 93.7 | 98.4 | 99.7 | -1.8 | 6.9  |

Accuracy to Comparator within Comparator Glucose Range (Adult)

|  CM Glucose Level (mg/dL) | Number of CGM-Reference Pairs | Percent Within ±15 mg/dL | Percent Within ±20 mg/dL | Percent Within ±40 mg/dL | Percent Within ±15% | Percent Within ±20% | Percent Within ±40% | Mean bias (mg/dL) | MARD (%)  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  <54 | 285 | 93.7 | 98.9 | 100.0 |  |  |  | 6.7 | 14.0  |
|  54-69 | 2059 | 94.7 | 98.7 | 100.0 |  |  |  | 0.5 | 10.1  |
|  70-180 | 5295 |  |  |  | 76.4 | 86.4 | 99.2 | -5.4 | 10.8  |
|  181-250 | 2138 |  |  |  | 86.6 | 93.1 | 99.5 | -8.2 | 8.3  |
|  >250 | 3557 |  |  |  | 91.5 | 96.1 | 99.6 | -10.7 | 6.9  |

Accuracy to Comparator within Comparator Glucose Range (Pediatric)

|  CM Glucose Level (mg/dL) | Number of CGM-Reference Pairs | Percent Within ±15 mg/dL | Percent Within ±20 mg/dL | Percent Within ±40 mg/dL | Percent Within ±15% | Percent Within ±20% | Percent Within ±40% | Mean bias (mg/dL) | MARD (%)  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  <54 | 93 | 94.6 | 97.8 | 100.0 |  |  |  | 6.6 | 13.9  |
|  54-69 | 460 | 96.3 | 99.1 | 100.0 |  |  |  | 0.1 | 8.1  |
|  70-180 | 1821 |  |  |  | 74.0 | 84.7 | 97.6 | -4.1 | 11.6  |
|  181-250 | 743 |  |  |  | 86.8 | 92.2 | 98.7 | -3.3 | 8.4  |
|  >250 | 1242 |  |  |  | 91.7 | 97.3 | 99.9 | -8.9 | 7.3  |

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Concurrence of iCGM values compared to the comparator method across the entire measuring range was also evaluated. iCGM glucose ranges of &lt;40, 40-60, 61-80, 81-120, 121-160, 161-200, 201-250, 251-300, 351-400 and &gt;400 mg/dL were evaluated against the comparator glucose ranges and percent of iCGM values within those ranges were reported.

Concurrence Analysis by iCGM Glucose Level (Adult)

|  iCGM (mg/dL) | CM (mg/dL) |   |   |   |   |   |   |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |  <40 | 40-60 | 61-80 | 81-120 | 121-160 | 161-200 | 201-250 | 251-300 | 301-350 | 351-400 | >400  |   |
|  <40 | 20.0 | 20.0 | 40.0 | 20.0 | . | . | . | . | . | . | . | 5  |
|  40-60 | 0.3 | 51.4 | 44.2 | 3.9 | . | 0.1 | . | . | . | . | . | 1458  |
|  61-80 | . | 16.7 | 61.0 | 21.8 | 0.5 | 0.0 | . | . | . | . | . | 2036  |
|  81-120 | . | 0.0 | 10.2 | 70.0 | 18.6 | 1.0 | 0.1 | . | . | . | . | 2147  |
|  121-160 | . | . | 0.1 | 8.7 | 68.6 | 19.9 | 2.0 | 0.4 | 0.3 | . | . | 1617  |
|  161-200 | . | . | . | . | 11.1 | 59.8 | 26.9 | 1.8 | 0.4 | . | . | 1246  |
|  201-250 | . | . | . | . | . | 7.5 | 65.6 | 24.8 | 2.0 | 0.1 | . | 1588  |
|  251-300 | . | . | . | . | . | 0.1 | 8.7 | 67.9 | 21.7 | 1.4 | 0.1 | 1670  |
|  301-350 | . | . | . | . | . | . | 0.5 | 14.4 | 68.7 | 14.9 | 1.5 | 1121  |
|  351-400 | . | . | . | . | . | . | . | 0.7 | 27.5 | 62.3 | 9.5 | 451  |
|  >400† | . | . | . | . | . | . | . | . | 2.7 | 65.5 | 31.8 | 110  |

Concurrence Analysis by iCGM Glucose Level (Pediatric)

|  iCGM (mg/dL) | CM (mg/dL) |   |   |   |   |   |   |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |  <40 | 40-60 | 61-80 | 81-120 | 121-160 | 161-200 | 201-250 | 251-300 | 301-350 | 351-400 | >400  |   |
|  <40 | . | 50.0 | 50.0 | . | . | . | . | . | . | . | . | 2  |
|  40-60 | 0.6 | 53.4 | 35.9 | 9.2 | 0.9 | . | . | . | . | . | . | 348  |
|  61-80 | . | 8.9 | 62.3 | 27.0 | 1.8 | . | . | . | . | . | . | 604  |
|  81-120 | . | 0.2 | 9.7 | 66.5 | 21.8 | 1.7 | 0.2 | . | . | . | . | 632  |
|  121-160 | . | . | . | 10.0 | 72.8 | 15.0 | 2.2 | . | . | . | . | 588  |
|  161-200 | . | . | . | 0.2 | 17.7 | 62.0 | 19.7 | 0.4 | . | . | . | 463  |
|  201-250 | . | . | . | . | 0.4 | 9.4 | 60.1 | 28.6 | 1.2 | 0.2 | . | 562  |
|  251-300 | . | . | . | . | . | 0.2 | 14.8 | 62.4 | 21.4 | 1.2 | . | 593  |
|  301-350 | . | . | . | . | . | . | . | 26.4 | 59.5 | 13.9 | 0.2 | 439  |
|  351-400 | . | . | . | . | . | 1.5 | . | 0.8 | 33.1 | 58.5 | 6.2 | 130  |
|  >400 | . | . | . | . | . | . | . | 6.9 | 6.9 | 31.0 | 55.2 | 29  |

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Concurrence Analysis by Comparator Glucose Level (Adult)

|  CM Glucose Level (mg/dL) | iCGM (mg/dL) |   |   |   |   |   |   |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |  <40 | 40-60 | 61-80 | 81-120 | 121-160 | 161-200 | 201-250 | 251-300 | 301-350 | 351-400 | >400  |   |
|  <40 | 16.7 | 83.3 | . | . | . | . | . | . | . | . | . | 6  |
|  40-60 | 0.1 | 68.7 | 31.1 | 0.1 | . | . | . | . | . | . | . | 1091  |
|  61-80 | 0.1 | 30.6 | 58.9 | 10.4 | 0.0 | . | . | . | . | . | . | 2108  |
|  81-120 | 0.0 | 2.7 | 20.7 | 70.1 | 6.5 | . | . | . | . | . | . | 2145  |
|  121-160 | . | . | 0.7 | 24.1 | 66.9 | 8.3 | . | . | . | . | . | 1657  |
|  161-200 | . | 0.1 | 0.1 | 1.8 | 26.6 | 61.5 | 9.8 | 0.2 | . | . | . | 1212  |
|  201-250 | . | . | . | 0.2 | 2.1 | 21.4 | 66.6 | 9.3 | 0.4 | . | . | 1563  |
|  251-300 | . | . | . | . | 0.4 | 1.3 | 22.9 | 65.9 | 9.3 | 0.2 | . | 1722  |
|  301-350 | . | . | . | . | 0.4 | 0.4 | 2.5 | 27.9 | 59.1 | 9.5 | 0.2 | 1302  |
|  351-400 | . | . | . | . | . | . | 0.4 | 4.4 | 30.6 | 51.5 | 13.2 | 546  |
|  >400 | . | . | . | . | . | . | . | 2.1 | 17.5 | 44.3 | 36.1 | 97  |

Concurrence Analysis by Comparator Glucose Level (Pediatric)

|  CM Glucose Level (mg/dL) | iCGM Glucose Level (mg/dL) |   |   |   |   |   |   |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   |  <40 | 40-60 | 61-80 | 81-120 | 121-160 | 161-200 | 201-250 | 251-300 | 301-350 | 351-400 | >400  |   |
|  <40 | . | 100.0 | . | . | . | . | . | . | . | . | . | 2  |
|  40-60 | 0.4 | 76.9 | 22.3 | 0.4 | . | . | . | . | . | . | . | 242  |
|  61-80 | 0.2 | 22.2 | 66.8 | 10.8 | . | . | . | . | . | . | . | 563  |
|  81-120 | . | 4.7 | 24.1 | 62.2 | 8.7 | 0.1 | . | . | . | . | . | 675  |
|  121-160 | . | 0.5 | 1.7 | 20.8 | 64.5 | 12.3 | 0.3 | . | . | . | . | 664  |
|  161-200 | . | . | . | 2.5 | 19.9 | 64.9 | 12.0 | 0.2 | . | 0.5 | . | 442  |
|  201-250 | . | . | . | 0.2 | 2.4 | 17.1 | 63.7 | 16.6 | . | . | . | 531  |
|  251-300 | . | . | . | . | . | 0.3 | 24.7 | 56.7 | 17.8 | 0.2 | 0.3 | 652  |
|  301-350 | . | . | . | . | . | . | 1.6 | 28.9 | 59.3 | 9.8 | 0.5 | 440  |
|  351-400 | . | . | . | . | . | . | 0.6 | 4.5 | 39.6 | 49.4 | 5.8 | 154  |
|  >400 | . | . | . | . | . | . | . | . | 4.0 | 32.0 | 64.0 | 25  |

## Trend Accuracy

Trend accuracy describes the accuracy of the sensor during times of rapidly changing glucose and is characterized by slopes, such as from $&gt;2\mathrm{mg/dL/min}$ to $&lt;-2\mathrm{mg/dL/min}$. Trend accuracy was assessed by the concurrence rate of the glucose rate of change from the iCGM and the corresponding comparator values for each iCGM-comparator measurement pair.

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Concurrence Analysis by Glucose Rate of Change (Adult)

|  CGM Rate Change (mg/dL/min) | CM Rate Change (mg/dL/min) |   |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   |  <-2 | [-2, -1) | [-1, 0) | [0, 1] | (1, 2] | >2  |   |
|  <-2 | 33.3 | 46.0 | 18.0 | 2.3 | 0.4 | -- | 261  |
|  [-2 to -1) | 6.6 | 44.6 | 42.8 | 4.3 | 1.1 | 0.6 | 807  |
|  [-1 to 0) | 1.2 | 8.5 | 66.8 | 19.6 | 2.7 | 1.2 | 6538  |
|  [0 to 1] | 1.0 | 3.3 | 26.1 | 46.9 | 15.8 | 6.9 | 3879  |
|  (1 to 2] | -- | 1.7 | 7.2 | 32.0 | 39.9 | 19.3 | 838  |
|  >2 | 0.3 | 0.3 | 3.5 | 15.4 | 32.9 | 47.7 | 663  |

Concurrence Analysis by Glucose Rate of Change (Pediatric)

|  CGM Rate Change (mg/dL/min) | CM Rate Change (mg/dL/min) |   |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   |  <-2 | [-2, -1) | [-1, 0) | [0, 1] | (1, 2] | >2  |   |
|  <-2 | 40.2 | 46.5 | 10.2 | 3.1 | -- | -- | 127  |
|  [-2 to -1) | 11.3 | 47.9 | 35.1 | 5.2 | 0.3 | 0.3 | 328  |
|  [-1 to 0) | 2.3 | 11.5 | 59.6 | 21.1 | 3.9 | 1.6 | 1633  |
|  [0 to 1) | 1.3 | 5.8 | 24.9 | 43.0 | 14.3 | 10.7 | 1416  |
|  (1 to 2] | 0.3 | 2.9 | 10.9 | 29.5 | 35.2 | 21.2 | 349  |
|  >2 | -- | 0.6 | 4.4 | 15.4 | 30.5 | 49.1 | 318  |

Agreement when iCGM Reads 'LO' or 'HI'

The System reports glucose readings between 40 and 400 mg/dL. When the System determines that glucose level is below 40 mg/dL, it will display 'LO' whenever the sensor is scanned. When the System determines that glucose level is above 400 mg/dL, it will display 'HI' whenever the sensor is scanned. Because the system does not display glucose values below 40 mg/dL or above 400 mg/dL, the comparisons to the actual blood glucose levels (as determined by the comparator) when the iCGM value is classified as 'LO' or 'HI' are evaluated separately. The cumulative percentages of when the comparator values were less than certain glucose values (for 'LO') and when comparator values were more that certain glucose values (for 'HI') are presented in the tables below.

Concurrence Analysis with 'LO' iCGM Reading (Adult)

|  iCGM-Reference Pairs | Comparator(mg/dL) |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- |
|   |  <50 | <60 | <70 | <80 | ≥80  |   |
|  n | 1 | 2 | 2 | 4 | 1 | 5  |
|  Cumulative % | 20.0 | 40.0 | 40.0 | 80.0 | 20.0 |   |

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Concurrence Analysis with 'LO' iCGM Reading (Pediatric*)

|  iCGM-Reference Pairs | Comparator (mg/dL) |   |   |   |   | N  |
| --- | --- | --- | --- | --- | --- | --- |
|   |  <50 | <60 | <70 | <80 | ≥80  |   |
|  n | 0 | 1 | 2 | 2 | 0 | 2  |
|  Cumulative % | 0.0 | 50.0 | 100.0 | 100.0 | 0.0 |   |

*Includes children 6-17 years of age. No CM measurements were obtained for children 4-5 years of age.

Concurrence Analysis with 'HI' iCGM Reading (Adult)

|  iCGM-Reference Pairs | Comparator (mg/dL) |   |   |   | N  |
| --- | --- | --- | --- | --- | --- |
|   |  >350 | >300 | >250 | >250  |   |
|  n | 107 | 110 | 110 | 0 | 110  |
|  Cumulative % | 97.3 | 100.0 | 100.0 | 0.0 |   |

Concurrence Analysis with 'HI' iCGM Reading (Pediatric*)

|  iCGM-Reference Pairs | Comparator (mg/dL) |   |   |   | N  |
| --- | --- | --- | --- | --- | --- |
|   |  >350 | >300 | >250 | >250  |   |
|  n | 25 | 27 | 29 | 0 | 29  |
|  Cumulative % | 86.2 | 93.1 | 100.0 | 0.0 |   |

*Includes children 6-17 years of age. No CM measurements were obtained for children 4-5 years of age.

## Alarm Performance

The tables in this section show the accuracy of the System's Low and High Glucose Alarms. The Alarm Rate tells the user how often the alarm is right or wrong. The Detection Rate tells the user how often the System is able to recognize and notify the user about a low or high glucose event (within 15 minutes before or after the event).

## Low Glucose Alarm Performance

True Alarm Rate: Percentage of time the alarm issued, and blood glucose was below the alarm level within 15 minutes before or after the alarm.

False Alarm Rate: Percentage of time the alarm issued, and blood glucose was not below the alarm level within 15 minutes before or after the alarm.

Detection Rate: Percentage of time blood glucose was below the alarm level and the alarm issued within 15 minutes before or after the glucose event.

Missed Detection Rate: Percentage of time blood glucose was below the alarm level and the alarm didn't issue within 15 minutes before or after the glucose event.

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Low Glucose Alarm Performance (Adult)

|  Low Glucose Alarm level (mg/dL) | Alarm Rate |   |   | Detection Rate  |   |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |  Hypo Alerts (n) | True Alarm Rate (%) | False Alarm Rate (%) | Hypo Events (n) | Correct Detection Rate (%) | Missed Detection Rate (%)  |
|  60 | 7585 | 72.5 | 27.5 | 1045 | 81.4 | 18.6  |
|  70 | 15776 | 84.8 | 15.2 | 2468 | 90.5 | 9.5  |
|  80 | 23510 | 89.7 | 10.3 | 3247 | 97.7 | 2.3  |
|  90 | 29792 | 92.5 | 7.5 | 3883 | 98.7 | 1.3  |

Low Glucose Alarm Performance (Pediatric*)

|  Low Glucose Alarm level (mg/dL) | Alarm Rate |   |   | Detection Rate  |   |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |  Hypo Alerts (n) | True Alarm Rate (%) | False Alarm Rate (%) | Hypo Events (n) | Correct Detection Rate (%) | Missed Detection Rate (%)  |
|  60 | 1879 | 67.9 | 32.1 | 247 | 96.0 | 4.0  |
|  70 | 4540 | 77.8 | 22.2 | 609 | 97.2 | 2.8  |
|  80 | 6697 | 84.7 | 15.3 | 835 | 97.7 | 2.3  |
|  90 | 8431 | 92.2 | 7.8 | 1061 | 98.2 | 1.8  |

* Includes children 6-17 years of age. No CM measurements were obtained for children 4-5 years of age.

High Glucose Alarm Performance

True Alarm Rate: Percentage of time the alarm issued, and blood glucose was above the alarm level within 15 minutes before or after the alarm.

False Alarm Rate: Percentage of time the alarm issued, and blood glucose was not above the alarm level within 15 minutes before or after the alarm.

Detection Rate: Percentage of time blood glucose was above the alarm level and the alarm issued within 15 minutes before or after the glucose event.

Missed Detection Rate: Percentage of time blood glucose was above the alarm level and the alarm didn't issue within 15 minutes before or after the glucose event.

High Glucose Alarm Performance (Adult; n=144)

|  High Glucose Alarm level (mg/dL) | Alarm Rate |   |   | Detection Rate  |   |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |  Hyper Alerts (n) | True Alarm Rate (%) | False Alarm Rate (%) | Hyper Events (n) | Correct Detection Rate (%) | Missed Detection Rate (%)  |
|  120 | 75744 | 99.2 | 0.8 | 8527 | 98.1 | 1/9  |
|  140 | 67834 | 99.2 | 0.8 | 7382 | 98.1 | 1.9  |
|  180 | 54571 | 99.1 | 0.9 | 5950 | 97.8 | 2.2  |

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|  High Glucose Alarm level (mg/dL) | Alarm Rate |   |   | Detection Rate  |   |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |  Hyper Alerts (n) | True Alarm Rate (%) | False Alarm Rate (%) | Hyper Events (n) | Correct Detection Rate (%) | Missed Detection Rate (%)  |
|  200 | 48663 | 99.2 | 0.8 | 5368 | 97.0 | 3.0  |
|  220 | 42372 | 98.9 | 1.1 | 4718 | 96.9 | 3.1  |
|  240 | 36198 | 98.6 | 1.4 | 4115 | 95.6 | 4.4  |
|  300 | 16638 | 96.1 | 3.9 | 2009 | 90.9 | 9.1  |

High Glucose Alarm Performance (Pediatric*; n=106)

|  High Glucose Alarm level (mg/dL) | Alarm Rate |   |   | Detection Rate  |   |   |
| --- | --- | --- | --- | --- | --- | --- |
|   |  Hyper Alerts (n) | True Alarm Rate (%) | False Alarm Rate (%) | Hyper Events (n) | Correct Detection Rate (%) | Missed Detection Rate (%)  |
|  120 | 23261 | 98.9 | 1.1 | 3035 | 97.9 | 2.1  |
|  140 | 20458 | 98.5 | 1.5 | 2701 | 98.0 | 2.0  |
|  180 | 15409 | 98.5 | 1.5 | 2123 | 98.0 | 2.0  |
|  200 | 13321 | 98.3 | 1.7 | 1907 | 98.1 | 1.9  |
|  220 | 11246 | 97.8 | 2.2 | 1690 | 96.9 | 3.1  |
|  240 | 9325 | 98.6 | 1.4 | 1484 | 96.1 | 3.9  |
|  300 | 4198 | 89.8 | 10.2 | 657 | 92.7 | 7.3  |

* Includes children 6-17 years of age. No CM measurements were obtained for children 4-5 years of age.

## Sensor Accuracy Over Time

Sensor accuracy over time (sensor stability) describes the performance of the sensor over the sensor lifetime. The FreeStyle Libre 2 MediRx sensor can be worn for up to 10 days. Performance was estimated by calculating the mean of the absolute relative differences between iCGM and comparator measurement and percentage of device readings within 15 mg/dL or 15% (15/15%), 20 mg/dL or 20% (20/20%) and 40 mg/dL or 40% (40/40%) of the comparator values during the beginning, middle, and end of the wear period. These times were defined as follows:

- Beginning (Adult Days 1-3, Pediatric: Days 1-2)
- Middle (Adult: Days 7-8, Pediatric: Days 7-8),
- End (Adult: Day 9, Pediatric: Day 9).

The mean absolute relative difference (MARD) and agreement rates with the comparator method were evaluated over 10-day life of the sensor.

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Sensor Accuracy Relative to Comparator Over the Wear Duration (Adult)

|  Sensor Wear Period | Number of CGM-reference pairs | MARD (%) | Within ±15% / ±15mg/dL | Within ±20% / ±20mg/dL | Within ±40% / ±40mg/dL  |
| --- | --- | --- | --- | --- | --- |
|  Beginning | 6955 | 9.9 | 83.4 | 90.4 | 99.3  |
|  Middle | 4522 | 8.5 | 87.7 | 94.5 | 99.8  |
|  End | 1857 | 9.0 | 86.4 | 93.8 | 99.6  |

Sensor Accuracy Relative to Comparator Over the Wear Duration (Pediatric*)

|  Day | Number of CGM-reference pairs | MARD (%) | Within ±15% / ±15mg/dL | Within ±20% / ±20mg/dL | Within ±40% / ±40mg/dL  |
| --- | --- | --- | --- | --- | --- |
|  Beginning | 1828 | 10.7 | 79.6 | 88.5 | 98.6  |
|  Middle | 1642 | 8.0 | 89.5 | 94.2 | 98.5  |
|  End | 889 | 9.8 | 82.9 | 92.1 | 99.4  |

* Includes children 6-17 years of age. No CM measurements were obtained for children 4-5 years of age.

## Sensor Life

To estimate how long a Sensor will work for the 10-day wear duration, 146 Sensors were evaluated in the Adult study and 139 Sensors were evaluated in the Pediatric study to determine how many days of readings each Sensor provided. Subjects did not wash the insertion site with soap and water before applying the Sensors and wore two Sensors simultaneously. Of the 146 Sensors in the Adult study, 82.2% lasted 10 days. In the Pediatric study, 89.9% of the Sensors lasted 10 days.

Sensor Survival Rate Over Wear Duration (Adult)

|  Day of Wear | Number of Sensors | Survival Rate (%)  |
| --- | --- | --- |
|  1 | 145 | 99.3  |
|  2 | 142 | 97.3  |
|  3 | 140 | 95.9  |
|  4 | 137 | 93.8  |
|  5 | 134 | 91.8  |
|  6 | 133 | 91.1  |
|  7 | 132 | 90.4  |
|  8 | 127 | 87.0  |
|  9 | 123 | 84.9  |
|  10 | 119 | 82.2  |

K211102 - Page 19 of 21

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Sensor Survival Rate Over Wear Duration (Pediatric)

|  Day of Wear | Number of Sensors | Survival Rate (%)  |
| --- | --- | --- |
|  1 | 137 | 98.6  |
|  2 | 136 | 97.8  |
|  3 | 134 | 97.1  |
|  4 | 133 | 96.4  |
|  5 | 133 | 96.4  |
|  6 | 133 | 96.4  |
|  7 | 133 | 96.4  |
|  8 | 131 | 94.9  |
|  9 | 126 | 91.3  |
|  10 | 124 | 89.9  |

A third clinical study was also conducted to further evaluate wear duration in subjects who first washed the insertion site with a plain soap and water, according to the full instructions in the labeling and wore only a single Sensor. A total of 39 Sensors were evaluated in this study, all the Sensors (100%) lasted 10 days.

## Glucose Reading Availability

The System is designed to show a Sensor glucose reading after each scan that is performed throughout the wear period after the start-up time. As such, the capture rate characterizes the reliability of the communication between components of the system.

Glucose Reading Capture Rate Over Wear Duration (Adult)

|  Day of Wear | Number of Sensors | Capture Rate (%)  |
| --- | --- | --- |
|  1 | 146 | 98.3  |
|  2 | 145 | 98.1  |
|  3 | 143 | 98.3  |
|  4 | 140 | 98.3  |
|  5 | 138 | 98.4  |
|  6 | 135 | 98.3  |
|  7 | 134 | 98.4  |
|  8 | 131 | 98.4  |
|  9 | 128 | 98.4  |
|  10 | 123 | 98.4  |

Glucose Reading Capture Rate Over Wear Duration (Pediatric)

|  Day of Wear | Number of Sensors | Capture Rate (%)  |
| --- | --- | --- |
|  1 | 139 | 94.6  |
|  2 | 137 | 94.9  |
|  3 | 136 | 95.2  |
|  4 | 133 | 95.3  |
|  5 | 134 | 95.5  |

K211102 - Page 20 of 21

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|  Day of Wear | Number of Sensors | Capture Rate (%)  |
| --- | --- | --- |
|  6 | 133 | 95.6  |
|  7 | 133 | 96.0  |
|  8 | 133 | 95.9  |
|  9 | 130 | 95.7  |
|  10 | 125 | 95.6  |

**D Clinical Cut-Off:**
Not applicable.

**E Expected Values/Reference Range:**
Not applicable.

**F Other Supportive Instrument Performance Characteristics Data:**

The FreeStyle Libre 2 Flash Glucose Monitoring System, when used with the FreeStyle Libre 2 MediRx Sensor, is identical to the predicate except for the sensor wear period. The following tests for the predicate device are leveraged in this 510(k):

- Human Factors
- Biocompatibility
- Sterilization
- Shelf Life and Stability
- Packaging Integrity/Shipping Integrity
- Electromagnetic Compatibility
- Electrical Safety
- Environmental Testing
- Blood Glucose Meter Functionality
- Interoperability
- Cybersecurity

**VIII Proposed Labeling:**

The labeling supports the finding of substantial equivalence for this device.

**IX Conclusion:**

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

K211102 - Page 21 of 21

---

**Source:** [https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/QLG/K211102](https://fda.innolitics.com/submissions/CH/subpart-b%E2%80%94clinical-chemistry-test-systems/QLG/K211102)

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