Lingo Glucose System

K233655 · Abbott · SAF · May 29, 2024 · Clinical Chemistry

Device Facts

• Record ID: K233655
• Device Name: Lingo Glucose System
• Applicant: Abbott
• Product Code: SAF · Clinical Chemistry
• Decision Date: May 29, 2024
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1355
• Device Class: Class 2

Indications for Use

The Lingo Glucose System is an over-the-counter (OTC) integrated Continuous Glucose Monitor (iCGM) intended to continuously measure, record, and display glucose values in people 18 years and older not on insulin. The Lingo Glucose System helps to detect euglycemic glucose levels. The Lingo Glucose System may also help the user better understand how lifestyle and behavior modification, including diet and exercise, impact glucose excursion. The user is not intended to take medical action based on the device output without consultation with a qualified healthcare professional.

Device Story

Lingo Glucose System is an OTC biowearable for non-insulin users to monitor glucose-lifestyle correlations. System comprises a single-use, 14-day subcutaneous electrochemical biosensor and a smartphone app (iOS). Biosensor measures interstitial glucose via amperometric reaction; calculates glucose values internally; transmits data via Bluetooth Low Energy (BLE) to the app. App displays real-time glucose values, trends, and graphs (55-200 mg/dL range). No alerts or alarms provided. User applies sensor to upper arm using a disposable applicator. Device intended for wellness/lifestyle management; users must consult healthcare professionals before taking medical action based on output. Benefits include improved understanding of how diet and exercise affect glucose excursions.

Clinical Evidence

No new clinical trials conducted. Substantial equivalence supported by leveraging clinical data from the predicate FreeStyle Libre 2 (K222447). Statistical analysis confirmed that the predicate's clinical performance data, which included higher glucose variability in diabetic subjects, represents a worst-case scenario for the subject device. System accuracy met iCGM special controls requirements per 21 CFR 862.1355.

Technological Characteristics

Amperometric electrochemical sensor; subcutaneous insertion; 14-day wear. Materials identical to predicate (ISO 10993-1 compliant). BLE connectivity (2.4 GHz). IP27 water resistance. Sterilization via electron beam (ISO 11137). Complies with IEC 60601-1, IEC 60601-1-2, IEC 60601-1-11, and CISPR 11. Wireless coexistence per AAMI TIR69/ANSI C63.27.

Indications for Use

Indicated for people 18 years and older not on insulin to continuously measure, record, analyze, and display glucose values. Helps detect euglycemic and dysglycemic levels and understand impact of lifestyle/behavior modifications on glucose. Not for medical action without professional consultation.

Regulatory Classification

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 (K222447)

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

K233655

B Applicant

Abbott Diabetes Care Inc.

C Proprietary and Established Names

Lingo Glucose System

D Regulatory Information

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

## II Submission/Device Overview:

A Purpose for Submission:

New device

B Measurand:

Glucose from 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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## III Intended Use/Indications for Use:

### A Intended Use(s):
See Indications for Use below.

### B Indication(s) for Use:
The Lingo Glucose System is an over-the-counter (OTC) integrated Continuous Glucose Monitor (iCGM) intended to continuously measure, record, analyze and display glucose values in people 18 years and older not on insulin. The Lingo Glucose System helps to detect euglycemic and dysglycemic glucose levels. The Lingo Glucose System may also help the user better understand how lifestyle and behavior modification, including diet and exercise, impact glucose excursion.

The user is not intended to take medical action based on the device output without consultation with a qualified healthcare professional.

### C Special Conditions for Use Statement(s):
OTC - Over The Counter

Do not use the Lingo Biosensor if you are on dialysis or critically ill. It is not known how different conditions or medications common to these populations may affect performance of the System.

Only apply the Lingo Biosensor to the back of the upper arm. If placed in other areas, the Lingo Biosensor may not function properly.

Taking more than 1000 mg of Vitamin C per day may falsely raise your Lingo Biosensor readings. Vitamin C can be found in supplements including multivitamins and cold remedies such as Airborne® and Emergen-C®. See your health care professional to understand how long Vitamin C is active in your body.

### D Special Instrument Requirements:
Not applicable

## IV Device/System Characteristics:

### A Device Description:
The Lingo Glucose System is a home use device that is intended to continuously measure the glucose in the interstitial fluid, calculate the glucose reading and make this value available to the user. The Lingo System can reliably and securely transmit glucose measurement data to authorized digitally connected devices. The system is not intended to be used in conjunction with insulin devices such as insulin pens and Automated Insulin Dosing (AID) systems. The Lingo Glucose System includes the Lingo Glucose Biosensor and the Lingo App.

#### Lingo Biosensor
The Lingo Glucose Biosensor hardware and technology is based on the FDA-cleared FreeStyle Libre 2 (FSL2) sensor (K222447). The Biosensor is a single use disposable on-body Biosensor

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that incorporates a subcutaneously implanted electrochemical glucose sensor and associated electronics. The Biosensor can be worn for up for 14 days and transmits data to the Lingo App via Bluetooth Low Energy (BLE).

## Lingo App (iOS)

The Lingo App is designed to work in conjunction with the Lingo Glucose Biosensor. The Lingo App, which is the primary display for the Lingo System, operates on an iOS-compatible mobile device and can be downloaded from the Apple App Store.

## B Principle of Operation:

The Lingo Glucose 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 an electrode, producing a current. The strength of the current is proportional to the amount of glucose present in the ISF. The system converts the electrical current signal to a glucose value (in mg/dL) for display to the user on a display device.

## C Instrument Description Information:

1. Instrument Name:
Lingo Glucose System

2. Specimen Identification:
Not applicable

3. Specimen Sampling and Handling:
Not applicable

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

5. Quality Control:
Not applicable

This medical device product has functions subject to FDA premarket review as well as functions that are not subject to FDA premarket review. For this application, if the product has functions that are not subject to FDA premarket review, FDA assessed those functions only to the extent that they either could adversely impact the safety and effectiveness of the functions subject to FDA premarket review or they are included as a labeled positive impact that was considered in the assessment of the functions subject to FDA premarket review.

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V Substantial Equivalence Information:

A Predicate Device Name(s):

FreeStyle Libre 2 Flash Glucose Monitoring System

B Predicate 510(k) Number(s):

K222447

C Comparison with Predicate(s):

| Device & Predicate Device(s): | K233655 | K222447 |
| --- | --- | --- |
| Device Trade Name | Lingo Glucose System | FreeStyle Libre 2 Flash Glucose Monitoring System |
| General Device Characteristic Similarities | | |
| Intended Use | Automatically measure glucose in bodily fluids continuously for a specified period of time. | Same |
| Principle of operation | Amperometric measurement of current proportional to glucose concentration in interstitial fluid via glucose oxidase chemical reaction. | Same |
| General Device Characteristic Differences | | |
| Intended Use Population | Persons 18 years and older not on insulin | Persons with diabetes age 2 years and older |
| Availability to user | Over the counter | Prescription use only |
| Glucose Measuring Range | 55 to 200 mg/dL | 40 to 400 mg/dL |
| Device features to manage diabetes | None | Alarms, glucose trend arrows, interoperability |
| Wear period | 14 days | 15 days |

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VI Standards/Guidance Documents Referenced:

- 21 CFR 862.1355 (integrated continuous glucose monitoring system (iCGM)) special controls
- ISO14971-2019-12 “Medical Devices-Application of Risk Management to Medical Devices”
- IEC 62304 -“Medical Device Software-Software Life Cycle Processes”
- IEC 60601-1-“Medical Electrical Equipment -Part 1: General Requirements for Basic Safety and Essential Performance”
- AAMI TIR69-“Risk Management of Radio-Frequency Wireless Coexistence for Medical Devices and Systems”
- AAMI TIR57: 2016- “Principles for medical device security – Risk management”
- IEC 60601-1-2-“Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral Standard: Electromagnetic disturbances - Requirements and tests”
- ISO 15223-1-“Medical Device-Symbols to be used with Medical Device Labels, Labeling and Information to be Supplied-Part 1: General Requirements”

VII Performance Characteristics (if/when applicable):

A Analytical Performance:

iCGM performance was evaluated using leveraged clinical studies from the predicate as the sensor component is identical. A new statistical analysis was performed to account for the different age range (predicate device is 2 years and older; subject device is 18 years and older), the truncated glucose measuring range (predicate device is 40 – 400 mg/dL; subject device is 55 – 200 mg/dL) and the shortened wear period (predicate device is 15 days; subject device is 14 days).

1. Precision/Reproducibility:

iCGM performance was evaluated in clinical studies described below in section C(3). Subjects wore two sensors concurrently, one on the back of each upper arm, to evaluate device precision.

In the study for all users, the mean paired absolute relative difference (between the 2 concurrently worn devices) was 8.4%; and the median coefficient of variation (median %CV) was 4.2%; mean %CV was 5.9%.

Precision Analysis

| Glucose Level (mg/dL) | Mean Coefficient of Variation (%) | Paired Absolute Difference (mg/dL) | Paired Absolute Relative Difference (%) | Number of Paired Readings | Number of Subjects |
| --- | --- | --- | --- | --- | --- |
| All | 5.9 | 9.2 | 8.4 | 14202 | 148 |

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2. Linearity:
See assay Reportable Range below.

3. Analytical Specificity/Interference:
Previously established in K222447.

4. Assay Reportable Range:
The reportable range for the Lingo Glucose Monitoring System is 55 to 200 mg/dL.

5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
The storage shelf-life of 9 months at 36 to 82 °F within the humidity range of 10% - 90% previously established for the predicate in K222447 is applicable to the subject device.

6. Detection Limit:
Not applicable

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 grade glucose measurement method.

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

C Clinical Studies:

1. Clinical Sensitivity:
Not applicable

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2. Clinical Specificity:

Not applicable

3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):

The clinical data of the predicate FreeStyle Libre 2 Flash Glucose Monitoring System (K222447) was reanalyzed to support the Lingo Glucose System.

The accuracy performance was assessed in a single pivotal clinical study conducted in the United States at seven centers.

The study enrolled 150 adult subjects with diabetes. Subjects wore two sensors for up to 16 consecutive days following Sensor application and accuracy analysis is based on the first applied sensor to each subject only. Subjects took part in up to three ten-hour clinical sessions that took place during four distinct periods: Days 1 to 3; Days 5 to 7; Days 9 to 11, and Days 13 to 15. During each clinic session, each subject's glucose was manipulated to observe data spanning the measuring range. Data from day 15 of wear are not considered in the following analyses.

Device accuracy was evaluated by comparing iCGM glucose values to glucose values from venous blood draws measured with an FDA-cleared laboratory grade comparator method (YSI 2300). Glucose values were obtained from the system and from the comparator at the same or similar time. Glucose values outside of the subject device measuring range are not included in the following analysis. Absolute differences in mg/dL of values compared to the comparator method were calculated for all values below 70 mg/dL. For values of 70 mg/dL and above, percentage differences compared to the comparator method were calculated.

Percent and Point Accuracy by iCGM Glucose Range

| iCGM Glucose Range (mg/dL) | No. Pairs | No. Subjects | Within 15 mg/dL (95% LB) | Within 40 mg/dL (95% LB) | Within 15% (95% LB) | Within 40% (95% LB) | Mean Bias (mg/dL) | MARD (%) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| <70 (55-69) | 2765 | 128 | 91.5 (89.4) | 99.6 (99.3) | | | -4.0 | 9.9 |
| 70 – 180 | 7513 | 148 | | | 82.1 (79.7) | 99.6 (99.4) | -6.3 | 9.7 |
| >180 (181-200) | 808 | 138 | | | 86.5 (83.0) | 99.9 (99.4) | -9.0 | 8.1 |

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Percent and Point Accuracy by Comparator Method (CM) Glucose Range

| CM Glucose Range (mg/dL) | No. Pairs | No. Subjects | Within 15 mg/dL (95% LB) | Within 40 mg/dL (95% LB) | Within 15% (95% LB) | Within 40% (95% LB) | Mean Bias (mg/dL) | MARD (%) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| < 70 (55-69) | 2386 | 120 | 96.9 (95.5) | 99.9 (99.6) | | | 1.4 | 8.9 |
| 70 – 180 | 7564 | 149 | | | 81.4 (79.0) | 99.6 (99.5) | -5.8 | 9.7 |
| >180 (181-200) | 1136 | 135 | | | 77.5 (73.3) | 99.4 (98.8) | -21.9 | 10.7 |

Percent of iCGM values within 20% of Comparator Glucose Values (N=149)

| iCGM Glucose Range | Matched Pairs (n) | Percent within 20% (95% LCL) |
| --- | --- | --- |
| 55-200 mg/dL | 11086 | 89.9 (88.0) |

## Concurrence

Concurrence of iCGM values compared to the comparator method across the entire measuring range was also evaluated. iCGM glucose ranges of &lt;55, 55-70, 71-90, 91-120, 121-160, 161-200, and &gt;200 mg/dL were evaluated against the comparator glucose ranges and the percentages of iCGM values within those ranges were reported in the following tables.

Concurrence of iCGM and Comparator by iCGM Glucose Range

| | Comparator Glucose Values (mg/dL) | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| iCGM (mg/dL) | <55 | 55-70 | 71-90 | 91-120 | 121-160 | 161-200 | >200 | Total |
| <55 | 39.5% | 48.4% | 9.9% | 1.8% | 0.1% | 0.1% | | 706 |
| 55-70 | 8.4% | 65.9% | 23.4% | 1.9% | 0.4% | | | 2913 |
| 71-90 | 0.4% | 16.5% | 52.5% | 28.4% | 2.3% | 0.1% | | 1851 |
| 91-120 | | 0.8% | 7.4% | 62.7% | 27.2% | 1.7% | 0.1% | 2200 |
| 121-160 | | 0.0% | 0.2% | 6.4% | 71.8% | 20.0% | 1.6% | 2355 |
| 161-200 | | | | 0.1% | 9.8% | 68.0% | 22.1% | 1767 |
| >200 | | | | | 0.1% | 2.4% | 97.5% | 7243 |

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Concurrence of iCGM and Comparator by Comparator Glucose Range

| | Comparator Glucose Values (mg/dL) | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| iCGM (mg/dL) | <55 | 55-70 | 71-90 | 91-120 | 121-160 | 161-200 | >200 |
| <55 | 52.6% | 13.2% | 3.7% | 0.6% | 0.0% | 0.1% | |
| 55-70 | 46.0% | 74.2% | 36.1% | 2.6% | 0.4% | | |
| 71-90 | 1.3% | 11.8% | 51.3% | 24.7% | 1.7% | 0.1% | |
| 91-120 | | 0.7% | 8.6% | 64.9% | 23.8% | 2.0% | 0.0% |
| 121-160 | | 0.0% | 0.3% | 7.1% | 67.1% | 25.0% | 0.5% |
| 161-200 | | | | 0.1% | 6.9% | 63.6% | 5.2% |
| >200 | | | | | 0.2% | 9.3% | 94.3% |
| Total | 530 | 2586 | 1892 | 2125 | 2521 | 1887 | 7494 |

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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;2mg/dL/min to &lt; -2 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.

Concurrence Analysis by Glucose Rate of Change

| iCGM Rate (mg/dL/min) | Comparator Rate (mg/dL/min) | | | | | |
| --- | --- | --- | --- | --- | --- | --- |
| | <-2 | [-2, -1) | [-1, 0) | [0, 1] | (1, 2] | >2 |
| <-2 | 41 (48.2%) | 61 (10.5%) | 28 (0.5%) | 5 (0.1%) | 2 (0.2%) | 1 (0.2%) |
| -2 to -1 | 22 (25.9%) | 197 (33.8%) | 166 (3.1%) | 23 (0.7%) | 5 (0.6%) | 2 (0.4%) |
| -1 to 0 | 18 (21.2%) | 280 (48.1%) | 4294 (80.8%) | 1261 (37.8%) | 101 (11.2%) | 52 (10.4%) |
| 0 to 1 | 4 (4.7%) | 43 (7.4%) | 807 (15.2%) | 1907 (57.1%) | 486 (53.9%) | 203 (40.5%) |
| 1 to 2 | 0 (0%) | 1 (0.2%) | 13 (0.2%) | 122 (3.7%) | 205 (22.8%) | 103 (20.6%) |
| >2 | 0 (0%) | 0 (0%) | 5 (0.1%) | 21 (0.6%) | 102 (11.3%) | 140 (27.9%) |
| Number of Paired iCGM-Comparator (N) | 85 | 582 | 5313 | 3339 | 901 | 501 |

Agreement when iCGM Reads “&lt; 55 mg/dL” or “&gt;200 mg/dL”

The Lingo Glucose System reports glucose readings between 55 and 200 mg/dL. When the system determines the sensor reading is below 55 mg/dL, it displays “&lt; 55 mg/dL” on the mobile app. When the system determines the sensor reading is above 200 mg/dL, it displays “&gt;200 mg/dL” on the mobile app. Because the system does not display glucose values below 55 mg/dL or above 200 mg/dL, the comparisons to the actual blood glucose levels (as determined by the comparator method) when the iCGM value is classified as “&lt; 55 mg/dL” or “&gt;200 mg/dL” is evaluated separately, and the cumulative percentages of when the comparator values were less than certain glucose values (for “&lt; 55 mg/dL”) and when comparator values were greater than certain values (for “&gt;200 mg/dL”) are presented in the tables below.

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Distribution of Comparator for iCGM Readings “&lt; 55 mg/dL”

| iCGM Readings | CGM- Comparator Pairs | Comparator (mg/dL) | | | | Total |
| --- | --- | --- | --- | --- | --- | --- |
| | | <70 | <90 | <120 | ≥120 | |
| <55 mg/dL | N | 621 | 691 | 704 | 2 | 706 |
| | Cumulative % | 88 | 97.9 | 99.7 | 0 | |

Distribution of Comparator for iCGM Readings “&gt; 200 mg/dL”

| iCGM Readings | CGM- Comparator Pairs | Comparator (mg/dL) | | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | >180 | >150 | >120 | >90 | >70 | ≤70 | |
| >200 mg/dL | n | 7226 | 7241 | 7243 | 7243 | 7243 | 0 | 7243 |
| | Cumulative % | 99.8 | 100 | 100 | 100 | 100 | 0 | |

## Sensor Stability

Sensor stability describes the performance of the sensor over the sensor lifetime. Sensors can be worn for up to 14 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, early middle, late middle, and end of the wear period. These times were defined as follows:

- Beginning (Days 1, 2 or 3)
- Early Middle (Days 5, 6 or 7),
- Late Middle (Days 9, 10 or 11), and
- End (Days 13 or 14).

The mean absolute relative difference (MARD) and agreement rates with the comparator method were evaluated over 14 day life of the sensor.

Accuracy of iCGM vs Comparator by Wear Period

| Wear Period | No. Pairs | MARD (%) | Within ±15% / ±15mg/dL | Within ±20% / ±20mg/dL | Within ±40% / ±40mg/dL |
| --- | --- | --- | --- | --- | --- |
| Beginning days (1-3) | 3281 | 11.5 | 78.1 | 86.3 | 98.8 |
| Early Middle days (5-7) | 2896 | 8.5 | 87.0 | 93.9 | 99.7 |
| Late Middle days (9-11) | 2927 | 8.8 | 86.6 | 93.4 | 99.2 |
| End days (13-14) | 1982 | 9.2 | 87.2 | 92.3 | 99.3 |

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Sensor Life

The sensor can be worn for up to 14 days. 151 Sensors were evaluated on the adult subjects to determine how many days of readings each Sensor provided.

Of the 151 sensors, 77.1% lasted until the final day of use. Some sensors were excluded from the analysis. For example, 4 sensors were intentionally removed due to subjects withdrawing or dropped out from the study early, one of which occurred during day 1 of the study. Of the sensors that did not last until the final day of use, 4 sensors (2.6%) had "early sensor shut-off" where the sensor algorithm detected that the sensor did not function as intended and automatically ended a sensor session. The Kaplan-Meier method was used to estimate how long a sensor will work over the wear duration.

Sensor Survival Rate Over Wear Duration

| Day of Wear | No. of Sensors | Survival Rate (%) |
| --- | --- | --- |
| 1 | 150 | 100.0 |
| 2 | 150 | 100.0 |
| 3 | 149 | 99.3 |
| 4 | 147 | 98.0 |
| 5 | 142 | 94.7 |
| 6 | 139 | 93.3 |
| 7 | 138 | 92.7 |
| 8 | 131 | 88.0 |
| 9 | 129 | 86.6 |
| 10 | 127 | 85.3 |
| 11 | 125 | 83.9 |
| 12 | 122 | 81.9 |
| 13 | 118 | 79.9 |
| 14 | 111 | 77.1 |

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# 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

| Day of Wear | No. of Sensors | Capture Rate (%) |
| --- | --- | --- |
| 1 | 146 | 96.4 |
| 2 | 146 | 97.4 |
| 3 | 146 | 97.7 |
| 4 | 142 | 97.8 |
| 5 | 143 | 97.9 |
| 6 | 141 | 97.9 |
| 7 | 136 | 98.1 |
| 8 | 135 | 98.1 |
| 9 | 130 | 98.2 |
| 10 | 127 | 98.3 |
| 11 | 125 | 98.2 |
| 12 | 123 | 98.2 |
| 13 | 118 | 98.2 |
| 14 | 116 | 98.2 |

## D Clinical Cut-Off:

Not applicable.

## E Expected Values/Reference Range:

Not applicable

## F Other Supportive Instrument Performance Characteristics Data:

The following supportive performance characteristics were established through nonclinical testing of the predicate device and are applicable to the Lingo Glucose System:

- Biocompatibility
- Sterilization Validation
- Shelf Life

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- Electrical and Mechanical Performance
- Operating Environmental Conditions Testing
- Wireless Coexistence
- Electrical Safety and Electromagnetic Compatibility
- Packaging Validation
- Interoperability

The following performance characteristics were verified or validated through studies conducted on the subject device, the Lingo Glucose System:

## Electromagnetic Compatibility

Electromagnetic compatibility (EMC) testing was performed for the Lingo Glucose System to verify that the system is able to withstand the electromagnetic interference and emissions in compliance with IEC 60601-1-2 and IEC CISPR 11. Wireless coexistence testing was performed to confirm that the sensor remains functional and perform within acceptable limits while in the presence of common radiating electronic devices in accordance with FDA Guidance “Radio Frequency Wireless Technology in Medical Devices.” The subject device underwent coexistence testing consistent with AAMI TIR69 and ANSI C63.27 and included test challenges from in-band interference sources defined in ANSI C63.27 as well as other expected wireless interference sources from the intended use environment. The Lingo Glucose System also successfully demonstrated compliance with Federal Communication Commission (FCC) Regulations Part 15.225 and Part 15.247, and Federal Aviation Administration (FAA) Advisory Circular RTCA DO-160.

## Mechanical Engineering

The subject device underwent performance testing at the system level as well as on individual components of the Sensor Applicator. The test results showed that mechanical, electrical, and functional testing all met the acceptance criteria.

## Software Verification and Validation

Software verification and validation testing was conducted in accordance with established specifications and IEC 62304 and documentation was provided as recommended by FDA Guidance “Content of Premarket Submissions for Device Software Functions,” issued June 14, 2023. Results of executed protocols met the acceptance criteria and therefore support that the sensor’s embedded software and the Lingo App software are acceptable for its intended use.

## Cybersecurity

Abbott has provided cybersecurity risk management documentation for the System that includes analysis of confidentiality, integrity, and availability for data, information and software related to the System accordance with FDA Guidance “Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions,” issued September 27, 2023. For each identified threat and vulnerability risk event scenario, risk assessment of impact to confidentiality integrity, and availability was performed and documented within the cybersecurity risk management documentation. Appropriate risk mitigation controls have been implemented and tested.

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## Human Factors

The user interface of the Lingo Glucose System has been found to support that the device is substantially equivalent to the predicate device for the intended users, uses, and use environments.

## 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.