Stelo Glucose Biosensor System
Device Facts
| Record ID | K260935 |
|---|---|
| Device Name | Stelo Glucose Biosensor System |
| Applicant | Dexcom, Inc. |
| Product Code | SBH · Clinical Chemistry |
| Decision Date | Jun 12, 2026 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 862.1355 |
| Device Class | Class 2 |
| Attributes | Software as a Medical Device, Real-World Evidence, Pediatric |
Real-World Evidence
| Submission | Device | Sponsor | RWD Sources | RWE Use Summary | Key Tags |
|---|---|---|---|---|---|
| K260935 · Jun 12, 2026 | Stelo Glucose Biosensor System | Dexcom, Inc. | Real-world usage trends of G7 and Stelo systems | RWE was used to compare pediatric and adult usage trends of the G7 and Stelo systems to support the extrapolation of adult Stelo performance data to pediatric users through day 15.5. | Usage trends; Pediatric extrapolation; Performance support |
Clinical Evidence
| Study Design | Population | Comparator | Key Endpoints |
|---|---|---|---|
| Real-world evidence (RWE) comparing pediatric and adult usage trends; Comparative analysis of usage trends | Pediatric and adult users of G7 and Stelo systems | Not applicable for this study | Usage trends |
Indications for Use
The Stelo Glucose Biosensor System is an over-the-counter (OTC) integrated Continuous Glucose Monitor (iCGM) intended to continuously measure, record, analyze, and display glucose values in people 2 years and older not on insulin. The Stelo Glucose Biosensor System helps to detect normal (euglycemic) and low or high (dysglycemic) glucose levels. The Stelo Glucose Biosensor System may also help the user better understand how lifestyle and behavior modification, including diet and exercise, impact glucose excursion.
Device Story
Stelo Glucose Biosensor System is an OTC, interoperable, factory-calibrated iCGM for home use; measures interstitial glucose via subcutaneous enzymatic electrochemical sensor (glucose oxidase); transmitter converts current to estimated glucose values (EGV) using Joint Probability Algorithm (JPA); transmits data via BLE to iOS/Android mobile app or Apple Watch app; provides real-time glucose display (55-350 mg/dL) and trend graphs; features 'Direct to Watch' (DTW) mode for independent smartwatch display; sensor wear life up to 15 days; helps users monitor glucose impact of lifestyle/diet; pediatric users (2-17) require caregiver supervision; sensor insertion on upper arm (or buttocks for ages 2-6).
Clinical Evidence
No new clinical study conducted. Pediatric performance (ages 2-17) supported by reprocessing pivotal clinical data from the Dexcom G7 (K213919) using the Stelo algorithm. Analysis included 164 pediatric subjects. Primary endpoints: MARD, percent accuracy within 15/15%, 20/20%, and 40/40% of YSI/SMBG comparator. Pediatric 7-17 YO arm MARD was 7.9% overall. Performance for days 11-15 extrapolated from adult data and G7 real-world evidence. Bench testing confirmed software, cybersecurity, and shelf-life specifications.
Technological Characteristics
Wire-type interstitial glucose sensing; BLE wireless communication; 15-day wear life; 18-month shelf life. Interoperable with iOS/Android mobile apps and watchOS. Software verification per IEC 62304. Cybersecurity controls per FDA guidance. Biocompatible materials; factory calibrated.
Indications for Use
Indicated for people 2 years and older not on insulin. Contraindicated for people on dialysis, with problematic hypoglycemia, those modifying medication without HCP consultation, or those with a history of eating disorders.
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
- Stelo Glucose Biosensor System (K234070)
Reference Devices
- Dexcom G7 Continuous Glucose Monitoring System (K213919)
- G7 10-Day DTW (K234133)
- G7 15-Day (K243214)
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
K260935
B Applicant
Dexcom, Inc.
C Proprietary and Established Names
Stelo Glucose Biosensor System
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| SBH | Class II | 21 CFR 862.1355 - Integrated Continuous Glucose Monitoring System | CH - Clinical Chemistry |
# II Submission/Device Overview:
A Purpose for Submission:
Modification to a cleared device to expand the indications for use to include people ages 2 years and older not on insulin, expand the glucose display range on the primary display device to 55-350 mg/dL, and include the "Direct to Watch" feature that enables direct BLE communication between the Stelo System Transmitter and a Watch App on a watchOS smartwatch, allowing Stelo iOS App users to use their smartwatch as an optional primary display.
B Measurand:
Glucose 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 Stelo Glucose Biosensor System is an over-the-counter (OTC) integrated Continuous Glucose Monitor (iCGM) intended to continuously measure, record, analyze, and display glucose values in people 2 years and older not on insulin. The Stelo Glucose Biosensor System helps detect normal (euglycemic) and low or high (dysglycemic) glucose levels. The Stelo Glucose Biosensor System may also help the user better understand how lifestyle and behavior modification, including diet and exercise, impact glucose excursion.
#### C Special Conditions for Use Statement(s):
OTC - Over The Counter
No MRI/CT/diathermy — MR unsafe: Don't wear any Stelo Glucose Biosensor system component during magnetic resonance imaging (MRI) or high-frequency electrical heat (diathermy) treatment. However, it's safe to have a CT scan if you keep the sensor out of the scanned area and cover the sensor with a lead apron during the scan. The Stelo Glucose Biosensor system hasn't been tested in those situations when used during an MRI scan, diathermy, or in the scanned area of a CT scan. The magnetic fields and heat could damage Stelo Glucose Biosensor system components, which may cause inaccurate sensor readings.
With the Stelo Glucose Biosensor system, you can take a standard or maximum acetaminophen dose of 1 gram (1,000 mg) every 6 hours and still use the Stelo Glucose Biosensor system. Taking higher than the maximum dose of acetaminophen (e.g. > 1 gram every 6 hours in adults) may affect the sensor readings and make them look higher than they really are.
If you are taking hydroxyurea, your sensor readings will be higher than your actual glucose. The level of inaccuracy depends on the amount of hydroxyurea in your body. Talk to your physician about alternative glucose monitoring approaches.
Don't use if you are on insulin. The Stelo Glucose Biosensor system hasn't been designed for these populations. Consult with your healthcare provider to discuss which Dexcom product is right for you.
Don't use if you have problematic hypoglycemia. The Stelo Glucose Biosensor system hasn't been designed for these populations. Consult with your healthcare provider to discuss which Dexcom product is right for you.
Don't use if you are on dialysis. The Stelo Glucose Biosensor system performance hasn't been evaluated in these populations and sensor readings may be inaccurate.
Consult your healthcare provider before using the Stelo Glucose Biosensor system if you have a history of disorderd eating or eating disorders.
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For those under 18 years of age, the Stelo Glucose Biosensor system is to be used under supervision of a caregiver.
Only insert your sensor on the back of your upper arm. Children from 2 to 6 years old can also choose their upper buttocks. Don't wear your sensor on other sites (such as your abdomen), as it may not work as expected.
#### **D Special Instrument Requirements:**
Not applicable
#### **IV Device/System Characteristics:**
##### **A Device Description:**
The Stelo Glucose Biosensor System (Stelo System) is an interoperable continuous glucose monitoring system (CGM). Same as the predicate (K234070), the Stelo 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 Stelo System can reliably and securely transmit glucose measurement data to authorized digitally connected devices. The Stelo System is not intended to be used in conjunction with insulin devices such as insulin pens and Automated Insulin Dosing (AID) systems. The system is a home use device and can be purchased over-the-counter (OTC).
The Stelo System has the same principle of operation, fundamental design, and physical characteristics as the predicate device.
The Stelo system consists of (1) a wearable, consisting of a sensor and transmitter worn on the body and (2) a receiving device, which acts as the primary display device, consisting of the Stelo Mobile Application (Mobile App) on an iOS or Android smart device. The Stelo System uses Bluetooth Low Energy (BLE) for wireless communication between these components. The user must pair the receiving device with each unique sensor to enable communication and start a sensor session. During an active session, the sensor reports new glucose data to the receiving device every 5 minutes. The receiving device then displays and updates glucose data to the user every 15 minutes. The sensor has an expected wear period of up to 15 days with an extended 12-hour grace period after the sensor session.
The Stelo System comprises of the following subsystems:
##### **1. Glucose Sensing Subsystem (GSS): Wearable (Sensor, Transmitter, and Patch) and Applicator**
The sensor is a small and flexible wire inserted by the applicator into subcutaneous tissue where it converts glucose into electric current. The transmitter is pre-connected to the sensor and is worn on the body by the adhesive patch. The transmitter measures the electric current produced by the sensor and converts these measurements into estimated glucose values (EGV) using an onboard algorithm. The transmitter sends glucose data to a display device (mobile app or watch app). Each GSS box also includes an overpatch, which is a general adhesive tape that helps with the adhesion of the wearable to the user's body.
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2. Mobile Applications (Mobile Apps): iOS and Android Stelo Mobile Application (iOS App and Android App)
The Stelo Mobile App is available on both iOS and Android platforms for users with a compatible BLE-enabled smart device. The Mobile App can be used as a primary display to receive and display glucose readings and trend graphs via BLE communication. The App provides in-app guidance for the user on how to apply and set up the wearable and how to create a user account. Once the set-up has been completed, the Mobile App receives information from the transmitter and acts as a user interface by indicating the system state (e.g., warm-up period, signal loss, etc.) and displaying glucose readings and trend graphs. The iOS App (Apple users) can also be used with the Watch Application. When the user downloads the iOS Mobile App from the Apple App Store, they automatically download the Stelo Watch App.
3. Watch Application (Watch App): Stelo Watch App
The Watch App is bundled as part of the iOS Mobile App software code and is by default automatically downloaded at the same time the user downloads their Mobile App from the Apple App Store. The Watch App can operate with either Direct to Watch (DTW) enabled (DTW mode) or DTW not enabled (Standard Smartwatch mode).
The Stelo System uses the same GSS firmware as the predicate device.
The Stelo Glucose Biosensor System has the following changes compared to the predicate:
- User interface for pediatrics users: The Stelo Mobile App was modified to include additional onboarding screens to ensure pediatrics users only use the device under adult supervision, and not to use the device if the user has or has a risk of eating disorders. The insertion instructions were modified to include users ages 7 years and older for inserting the sensor on the back of the upper arm, and to include the option of inserting the sensor on the buttocks for users ages 2-6.
- Expanded real-time glucose display range: The real-time display glucose range in the Stelo apps was modified. The lower limit was changed from 70 mg/dL to 55 mg/dL, and the upper limit was changed from 250 mg/dL to 350 mg/dL. This UI change is reflected everywhere the glucose range is displayed to the user in the Stelo Mobile app (e.g., trend graph, EGV card). Similar to how the displayed glucose range functioned at 70-250 mg/dL, if the glucose data received from the transmitter exceeds the upper or lower limit of 55-350 mg/dL, the UI will indicate to the user that they are above or below the displayable limit, respectively. The retrospective display range remains unchanged (40-400 mg/dL).
- Direct to watch (DTW): The Stelo Watch App was modified to add the DTW Enabled (DTW mode) smartwatch feature, which allows the Watch App to connect directly with the Stelo Transmitter. With DTW enabled, the Watch App can act as a primary display when the phone is not in range of the wearable (sensor, transmitter). This means that users are not required to keep their smart phones in close proximity to their Watch App in order to receive EGVs and notifications and can instead receive glucose data on their smartwatch directly from the transmitter. The Stelo Mobile App (iOS only) was also
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modified to add the DTW feature. Once the sensor session has started on the Mobile App, if the user has a compatible smartwatch paired with their phone, the Mobile App will instruct the watch app to pair with the transmitter. The watch app will then send a pairing request to the user to initiate DTW mode. If the user declines the pairing request, the transmitter and watch will not pair and the transmitter will send EGVs through the mobile app to the watch app instead (Standard Smartwatch mode). All settings of the Stelo Watch app are only configurable on the Stelo Mobile App.
### B Principle of Operation:
The Stelo System detects glucose levels from the fluid just beneath the skin (interstitial fluid). The sensor probe continuously measures glucose concentration in the interstitial fluid via an enzymatic electrochemical reaction using glucose oxidase. The enzyme, glucose oxidase, catalyzes the oxidation of glucose and produces hydrogen peroxide. The production of hydrogen peroxide generates an electrical current that is proportionate to the interstitial glucose concentration. The transmitter converts the signal using an algorithm to a glucose value read in mg/dL, which is then transmitted to the mobile application for the user to see and use accordingly.
### C Instrument Description Information:
1. Instrument Name:
Stelo Glucose Biosensor System
2. Specimen Identification:
Not applicable
3. Specimen Sampling and Handling:
Not applicable
4. Calibration:
The Stelo Glucose Biosensor System is factory calibrated. Users may not enter optional calibrations based on fingerstick blood glucose values.
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):**
Stelo Glucose Biosensor System
# **B Predicate 510(k) Number(s):**
K234070
# **C Comparison with Predicate(s):**
| Device & Predicate Device(s): | K260936 | K234070 |
| --- | --- | --- |
| Device Trade Name | Stelo Glucose Biosensor System | Stelo Glucose Biosensor System |
| **General Device Characteristic Similarities** | | |
| Intended Use/Indications For Use | Continuously measure, record, analyze, and display glucose values to help detect normal (euglycemic) and low or high (dysglycemic) glucose levels. | Same |
| Type of Use | Over-the-counter use | Same |
| Glucose and System Alerts | None | Same |
| Use Setting | Home use | Same |
| Sensor Calibration | Factory calibrated only | Same |
| Sensor Warmup Time | Within 30 minutes (27 minutes) | Same |
| Sensor Use Life | Up to 15 days with 12 hour grace period (automatic sensor shut off) | Same |
| Algorithm | Joint Probability Algorithm (JPA) | Same |
| Measurement range | 40-400 mg/dL | Same |
| BLE Communication Range | 20 feet unobstructed | Same |
| Compatible Mobile Operating Systems | iOS and Android | Same |
| **General Device Characteristic Differences** | | |
| Intended Use Population | Persons who are not on insulin therapy age 2 | Persons who are not on insulin therapy age 18 |
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| | years and older | years and older |
| --- | --- | --- |
| Primary Display Device | Mobile app or Watch app (Apple users only) | Mobile app |
| Real-time Display Range | 55-350 mg/dL | 70-250 mg/dL |
## VI Standards/Guidance Documents Referenced:
- • 21 CFR 862.1355 (integrated continuous glucose monitoring system (iCGM)) special controls
- • ISO 14971 Third Edition 2019-12, Medical devices - Applications of risk management to medical devices
- • IEC 62304:2006/A1:2016, Medical device software - Software life cycle processes [Including Amendment 1 (2016)]
- • ANSI AAMI IEC 60601-1-2:2014 [Including AMD 1:2021], Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral Standard: Electromagnetic disturbances - Requirements and tests [Including Amendment 1 (2021)]
- • AIM Standard 7351731 Rev. 3.00 2021-06-04, Medical Electrical Equipment and System Electromagnetic Immunity Test for Exposure to Radio Frequency Identification Readers - An AIM Standard
- • ANSI AAMI HE75:2009/(R)2018, Human factors engineering - Design of medical devices
- • IEC 62366-1 Edition 1.1 2020-06 CONSOLIDATED VERSION, Medical devices - Part 1: Application of usability engineering to medical devices
- • IEC 60601-1 Edition 3.2 2020-08 CONSOLIDATED VERSION, Medical Electrical Equipment: General requirements for basic safety and essential performance
- • IEC 60601-1-6 Edition 3.2 2020-07 CONSOLIDATED VERSION, Medical electrical equipment - Part 1-6: General requirements for basic safety and essential performance - Collateral standard: Usability
- • IEC 60601-1-11 Edition 2.1 2020-07 CONSOLIDATED VERSION, Medical Electrical Equipment, Part 1-11: General requirements for basic safety and essential performance- Collateral Standard: Requirements for medical electrical equipment and medical electrical systems used in the home healthcare environment
- • IEC TR 60601-4-2 Edition 1.0 2016-05, Medical electrical equipment - Part 4-2: Guidance and interpretation - Electromagnetic immunity: performance of medical electrical equipment and medical electrical systems
- • IEEE ANSI USEMCSC C63.27-2021, American National Standard for Evaluation of Wireless Coexistence
- • AAMI TIR69:2017/(R2020), Technical Information Report Risk management of radio-frequency wireless coexistence for medical devices and systems.
- • ISO 10993-7 Second edition 2008-10-15, Biological evaluation of medical devices - Part 7: Ethylene oxide sterilization residuals [Including: Technical Corrigendum 1 (2009), AMENDMENT 1: Applicability of allowable limits for neonates and infants (2019)]
- • ISO 11135 Second edition 2014-07-15, Sterilization of health-care products - Ethylene oxide - Requirements for the development, validation and routine control of a sterilization process for medical devices [Including: Amendment 1 (2018)]
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- • ISO 11737-1 Third edition 2018-01 [Including AMD1:2021], Sterilization of health care products - Microbiological methods - Part 1: Determination of a population of microorganisms on product [Including Amendment 1 (2021)]
- • ISO 11737-2 Third edition 2019-12, Sterilization of medical devices - Microbiological methods - Part 2: Tests of sterility performed in the definition, validation and maintenance of a sterilization process
- • ISO 11138-1 Third edition 2017-03, Sterilization of health care products - Biological indicators - Part 1: General requirements
- • Content of Premarket Submissions for Device Software Functions
- • Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions
- • Applying Human Factors and Usability Engineering to Medical Devices
- • Design Considerations for Devices intended for Home Use
- • Radio Frequency Wireless Technology in Medical Devices
- • Recommended Content and Format of Non-Clinical Bench Performance Testing Information in Premarket Submissions
- • Design Considerations and Pre-market Submission Recommendations for Interoperable Medical Devices
- • Off-the-Shelf Software Use in Medical Devices
- • Multiple Function Device Products: Policy and Considerations
- • Deciding When to Submit a 510(k) for a Software Change to an Existing Device
- • Deciding When to Submit a 510(k) for a Change to an Existing Device
## VII Performance Characteristics (if/when applicable):
### A Analytical Performance:
Stelo Glucose Biosensor performance in adults 18 years and older was established in K234070. To account for the expanded user age range for the Stelo Glucose Biosensor in this 510(k), the pediatric clinical data from the 10-Day Dexcom G7 Continuous Glucose Monitoring (CGM) System reference device (K213919) was reprocessed using the subject device algorithm to evaluate pediatric performance for up to 10.5 days. To estimate performance of the Stelo Glucose Biosensor in pediatrics from 10.5 days through 15 days, performance in adults 18 years and older was extrapolated as described below. The Stelo Glucose Biosensor performance evaluation in pediatric subjects is described below in section C(3).
#### 1. Precision/Reproducibility:
Adult performance was previously established in K234070.
Stelo Glucose Biosensor performance in pediatric populations was evaluated using clinical data originally collected with the Dexcom G7 10-day CGM sensor, which was reprocessed with the Stelo system algorithm as described below in Section C(3). A subset of pediatric subjects wore two G7 Systems at the same (N=12). A total of eight pediatric subjects aged 7-17 years old and one pediatric subject aged 2-6 years old wore two G7 Systems concurrently at the arm wear location. A total of three pediatric subjects aged 2-6 years old wore two G7 Systems concurrently at the upper buttocks location. Precision was evaluated by comparing the glucose readings from the two systems worn by the same subject on the same location.
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# **Precision by Insertion Site and Age – Pediatrics 2-17 YO**
| | 2-6 YO | | 7-17 YO |
| --- | --- | --- | --- |
| | Arm | Upper Buttocks* | Arm |
| CGM-CGM Matched Pairs (n) | 2,640 | 6,566 | 23,814 |
| Number of Subjects (N) | 1 | 3 | 8 |
| Paired Absolute Difference (mg/dL) | 12.2 | 11.1 | 13.6 |
| Paired Absolute Relative Difference (%) | 5.8 | 7.5 | 8.7 |
| Coefficient of Variation (%) | 4.1 | 5.3 | 6.2 |
*Only pediatrics aged between 2-6 YO wore devices on the upper buttocks.
# 2. Linearity:
The measurement range of the System is 40-400 mg/dL and the real-time reportable range is 55-350 mg/dL. Data supporting this claimed measurement range was generated in the clinical studies described in Section C(3) below.
# 3. Analytical Specificity/Interference:
Previously established in K234070.
Users of the Stelo Glucose Biosensor System can take a standard or maximum dose of acetaminophen (up to 1 gram every 6 hours in adults) and still use the Stelo System readings. Sensor glucose readings will be falsely higher if the user is taking more than a standard acetaminophen dose.
Sensor glucose readings will also be falsely higher if the user is taking hydroxyurea. Users should talk to their physician about alternative glucose monitoring approaches if they are taking hydroxyurea.
# 4. Detection Limit and Assay Reportable Range:
See Linearity section above.
If a glucose measurement is less than 55 mg/dL, the result is displayed by the system as “Below 55 mg/dL.” If a glucose measurement exceeds 350 mg/dL, the result is displayed as “Above 350 mg/dL.” Users can view historical results across the full device measurement range (40-400 mg/dL) via Dexcom Clarity, a cloud-based software available on the web and on apps.
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5. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
The Stelo GSS (sensor and transmitter) has a storage shelf-life of up to 18 months. Shelf life was evaluated at 86°F. Sensors should be stored at 36°- 86°F and 10-90% relative humidity.
6. Assay Cut-Off:
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 analyzer (Yellow Springs Instrument 2300 STAT Plus™ Glucose Analyzer) and referred to as the “comparator method” in Section C(3) below.
2. Matrix Comparison:
Not applicable. Interstitial fluid is the only indicated matrix.
# **C Clinical Studies:**
1. Clinical Sensitivity:
Not applicable.
2. Clinical Specificity:
Not applicable.
3. Other Clinical Supportive Data (When 1. and 2. Are Not Applicable):
The analytical and clinical performance of the Stelo Glucose Biosensor System (Stelo) in users 18 years and older for up to 15.5 days was previously established in K234070.
No new clinical study was conducted to evaluate the Stelo in pediatric subjects (ages 2 to 17). To support Stelo analytical and clinical performance in pediatric users 2 to 17 years for up to 10.5 days, the previously conducted pivotal study of the 10-Day Dexcom G7 Continuous Glucose Monitoring System (Dexcom G7 System or G7) from K213919 was reanalyzed using the Stelo algorithm. The G7 has the same fundamental design, physical characteristics, and principle of operation as the Stelo system, so the reprocessed results are expected to be representative of what would have been observed if Stelo devices were used in that study. That study enrolled 164 pediatric subjects age 2 to 17 years old with type 1 diabetes on intensive insulin therapy (IIT) at seven U.S. clinic sites. Subjects ages 2 to 6 wore the device on the upper arm and upper buttocks, while subjects ages 7 to 17 wore the device on the upper arm. The effectiveness of the device was evaluated with respect to reference venous plasma sample YSI measurements for ages 7 to 17 years of age, and reference capillary sample blood glucose measurements for ages 2
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to 6 years of age, across the measuring range throughout a 10-day wear duration with a 12-hour grace period.
Stelo pediatric performance during days 10.5 to 15.5 was not directly studied and was supported by extrapolation. A clinical assessment was provided based on comparative analyses of G7 10-Day and Stelo System clinical data across and within adult and pediatric cohorts, accounting for algorithm differences, glucose range, and wear duration. The Stelo device uses the same sensor as the predicate studied in adults (K234070), as well as the G7 CGM System studied in pediatrics and adults (K213919), providing a high degree of confidence in the estimates of pediatric performance through day 10.5 for the Stelo system. Real-world evidence (RWE) comparing pediatric and adult usage trends of G7 and Stelo was also generated and considered in the substantial equivalence determination, providing additional support for extrapolating adult Stelo performance to pediatric users through day 15.5. Residual performance uncertainty is acceptable considering these data together with the indications for use of the Stelo System. Based on the design of the Stelo, as well as available performance data and additional RWE from G7 10-Day and Stelo systems, it is reasonable to expect that pediatric sensor accuracy may be comparable to adult sensor accuracy through day 15.5, and that pediatric sensor survival is likely to be lower than adult sensor survival.
Data from the reanalyzed G7 study to support pediatric performance up to 10.5 days are presented in the tables below. Although the real-time reporting range of the system is 55-350 mg/dL, users can view the full device measurement range of 40-400 mg/dL retrospectively via Dexcom Clarity. Therefore, the device performance across the full measuring range was included in the analyses below and considered in the substantial equivalence determination.
### **iCGM Reading Accuracy to Comparator**
Below are the percent values of 15%/15 mg/dL, and 40%/40 mg/dL stratified by glucose ranges of <70, 70-180, and >180mg/dL for the iCGM and comparator. The 95% CI in the below tables is the 95% confidence interval (two-sided, alpha = 0.05), and the 95% LB is the lower bound of 95% confidence limit (one-sided, alpha = 0.05).
### **Percent and Point Accuracy Between iCGM and Comparator by iCGM Glucose Range - Pediatrics 7-17 YO Arm (N=122)**
| **iCGM Glucose Range^{1} (mg/dL)** | **Matched Pairs (N)** | **Percent within 15 mg/dL (95% LB)** | **Percent within 40 mg/dL (95% LB)** | **Percent within 15% (95% LB)** | **Percent within 40% (95% LB)** | **Mean Bias (mg/dL) (95% CI)** |
| --- | --- | --- | --- | --- | --- | --- |
| <70 | 791 | 89.8 (83.6) | 97.4 (92.6) | --- | --- | -7.2 (-9.8, -4.6) |
| 70-180 | 4,132 | --- | --- | 86.3 (82.3) | 99.8 (99.4) | -4.4 (-6.8, -2.1) |
| >180 | 3,179 | --- | --- | 90.9 (87.5) | 100.0 (99.9) | -0.9 (-3.5, 1.7) |
$^{1}$iCGM readings are within 40-400 mg/dL, inclusive
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# **Percent and Point Accuracy Between iCGM and Comparator by Comparator Glucose
Range - Pediatrics 7-17 YO Arm (N=122)**
| Comparator Glucose Range^{1} (mg/dL) | Matched Pairs (N) | Percent within 15 mg/dL (95% LB) | Percent within 40 mg/dL (95% LB) | Percent within 15% (95% LB) | Percent within 40% (95% LB) | Mean Bias (mg/dL) (95% CI) |
| --- | --- | --- | --- | --- | --- | --- |
| <70 | 884 | 95.0 (91.5) | 100.0 (100.0) | --- | --- | -0.3 (-2.5, 2.0) |
| 70-180 | 3,933 | --- | --- | 87.6 (83.9) | 98.8 (97.7) | -2.2 (-4.4, 0.0) |
| >180 | 3,285 | --- | --- | 88.9 (85.0) | 99.9 (99.7) | -5.0 (-7.5, -2.4) |
$^{1}$ iCGM readings are within 40-400 mg/dL, inclusive
The Stelo percent and point accuracy between iCGM and the comparator for Days 1-10 is comparable to that of the predicate (K234070).
The percent of values within 20% of the comparator method were calculated across the measuring range overall.
# **Percent of iCGM Values within 20% of Comparator Glucose by Study Population and Wear Location**
| Study Population | Matched Pairs (n) | Percent within 20% (95% LB) |
| --- | --- | --- |
| **Pediatrics (7-17 years old)** Arm (N=122) | 8,102 | 94.7 (92.8) |
| **Pediatrics (2 - 6 years old)^{1}** Arm (N=14) Upper buttocks (N=14) | 148 152 | 97.2 (93.2) 88.9 (81.8) |
$^{1}$ No YSI measurements were taken for pediatrics 2-6 YO; results presented are from in-clinic CGM-SMBG matched paired measurements.
The percent of values within 15%/15 mg/dL, 20%/20 mg/dL, and 40%/40 mg/dL stratified by glucose ranges of <55, 55-69, 70-180, 181-250, 251-350, and >350 mg/dL for the iCGM and comparator were also provided for arm insertion site.
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# **System Accuracy to Comparator within iCGM Glucose Ranges - Pediatrics 7-17 YO Arm (N=122)**
| iCGM Glucose Range^{1} (mg/dL) | Matched Pairs (N) | 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 (%) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| <55 | 144 | 65.3 | 75.0 | 94.4 | --- | --- | --- | -15.8 | 22.5 |
| 55-69 | 647 | 90.1 | 94.0 | 97.1 | --- | --- | --- | -3.5 | 9.3 |
| 70-180 | 4,132 | --- | --- | --- | 85.7 | 93.4 | 99.8 | -0.6 | 8.3 |
| 181-250 | 1,311 | --- | --- | --- | 87.6 | 95.7 | 99.9 | -5.7 | 7.3 |
| 251-350 | 1,539 | --- | --- | --- | 92.4 | 99.4 | 100.0 | -9.9 | 6.4 |
| >350 | 329 | --- | --- | --- | 97.6 | 100.0 | 100.0 | -1.3 | 4.5 |
$^{1}$ iCGM readings are within 40-400 mg/dL, inclusive
# **System Accuracy to Comparator within Comparator Glucose Ranges - Pediatrics 7 -17 YO Arm (N=122)**
| Comparator Glucose Range (mg/dL) | Matched Pairs^{1} (N) | 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 (%) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| <55 | 81 | 95.1 | 97.5 | 100.0 | --- | --- | --- | 3.2 | 11.7 |
| 55-69 | 803 | 91.9 | 97.5 | 100.0 | --- | --- | --- | 2.3 | 10.0 |
| 70-180 | 3,933 | --- | --- | --- | 86.8 | 93.4 | 98.8 | -0.3 | 8.2 |
| 181-250 | 1,275 | --- | --- | --- | 88.4 | 95.5 | 99.8 | -4.6 | 7.4 |
| 251-350 | 1,605 | --- | --- | --- | 88.5 | 96.9 | 100.0 | -11.4 | 7.0 |
| >350 | 405 | --- | --- | --- | 94.1 | 100.0 | 100.0 | -17.3 | 5.8 |
$^{1}$ iCGM readings are within 40-400 mg/dL, inclusive
To reflect the expanded glucose display range from 70-250 mg/dL to 55-350 mg/dL, the updated analysis is also provided for adults below based on the adult pivotal study from K234070 conducted on the predicate.
# **System Accuracy to Comparator within iCGM Glucose Ranges - Adults (N=130)**
| iCGM glucose range^{1} (mg/dL) | Matched pairs (N) | 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 (%) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| <55 | 337 | 72.7 | 86.4 | 99.7 | --- | --- | --- | -9.6 | 16.7 |
| 55-69 | 1,470 | 92.8 | 96.5 | 99.5 | --- | --- | --- | -2.1 | 9.1 |
| 70-180 | 10,902 | --- | --- | --- | 84.8 | 93.3 | 99.6 | -1.1 | 8.5 |
| 181-250 | 3,301 | --- | --- | --- | 84.3 | 91.5 | 100.0 | -11.3 | 8.3 |
| 251-350 | 3,924 | --- | --- | --- | 91.0 | 96.5 | 100.0 | -10.9 | 6.9 |
| >350 | 396 | --- | --- | --- | 97.2 | 100.0 | 100.0 | 7.1 | 4.9 |
$^{1}$ iCGM readings are within 40-400 mg/dL, inclusive
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System Accuracy to Comparator within Comparator Glucose Ranges - Adults (N=130)
| Comparator glucose range (mg/dL) | Matched pairs^{1} (N) | 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 (%) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| <55 | 258 | 90.7 | 94.2 | 98.8 | --- | --- | --- | 5.1 | 14.6 |
| 55-69 | 1,750 | 93.9 | 97.8 | 100.0 | --- | --- | --- | 1.8 | 9.9 |
| 70-180 | 10,463 | --- | --- | --- | 86.2 | 93.8 | 99.7 | -0.3 | 8.2 |
| 181-250 | 2,988 | --- | --- | --- | 88.0 | 94.9 | 99.9 | -6.5 | 7.4 |
| 251-350 | 4,248 | --- | --- | --- | 86.9 | 93.4 | 99.9 | -13.8 | 7.8 |
| >350 | 623 | --- | --- | --- | 80.1 | 86.5 | 100.0 | -29.2 | 9.1 |
$^{1}$ iCGM readings are within 40-400 mg/dL, inclusive
## Concurrence
Adult performance was previously established in K234070.
Concurrence of iCGM values compared to the comparator method across the entire measuring range was also evaluated. iCGM glucose ranges of <40, 40-60, 61-80, 81-120, 121-160, 161-200, 201-250, 251-300, 301-350, 351-400, and >400 mg/dL were evaluated against the comparator glucose ranges, and the percent of iCGM values within those ranges were reported in the following tables.
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# **Concurrence of iCGM and Comparator by iCGM Glucose Range - Pediatrics 7-17 YO Arm (N=122)**
| iCGM (mg/dL) | Comparator Glucose Values (mg/dL) | | | | | | | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | <40 | 40-60 | 61-80 | 81-120 | 121-160 | 161-200 | 201-250 | 251-300 | 301-350 | 351-400 | >400 | |
| **<40** | 2 2.9% | 24 34.8% | 38 55.1% | 5 7.2% | --- | --- | --- | --- | --- | --- | --- | 69 |
| **40-60** | 1 0.3% | 156 48.9% | 143 44.8% | 15 4.7% | 4 1.3% | --- | --- | --- | --- | --- | --- | 319 |
| **61-80** | --- | 98 8.9% | 894 80.8% | 102 9.2% | 11 1.0% | 2 0.2% | --- | --- | --- | --- | --- | 1,107 |
| **81-120** | --- | 4 0.2% | 327 20.3% | 1,118 69.4% | 159 9.9% | 3 0.2% | --- | --- | --- | --- | --- | 1,611 |
| **121-160** | --- | --- | --- | 159 11.8% | 945 70.1% | 228 16.9% | 16 1.2% | --- | --- | --- | --- | 1,348 |
| **161-200** | --- | --- | --- | --- | 146 15.3% | 611 64.1% | 186 19.5% | 10 1.0% | --- | --- | --- | 953 |
| **201-250** | --- | --- | --- | --- | --- | 105 11.7% | 593 66.2% | 185 20.6% | 13 1.5% | --- | --- | 896 |
| **251-300** | --- | --- | --- | --- | --- | --- | 66 8.7% | 353 46.8% | 332 44.0% | 4 0.5% | --- | 755 |
| **301-350** | --- | --- | --- | --- | --- | --- | --- | 59 7.5% | 589 75.1% | 136 17.3% | --- | 784 |
| **351-400** | --- | --- | --- | --- | --- | --- | --- | 1 0.3% | 63 19.1% | 235 71.4% | 30 9.1% | 329 |
| **>400** | --- | --- | --- | --- | --- | --- | --- | --- | 1 2.2% | 21 45.7% | 24 52.2% | 46 |
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# **Concurrence of iCGM (40-400 mg/dL) and Comparator by Comparator Glucose Range - Pediatrics 7-17 YO Arm (N=122)**
| iCGM (mg/dL) | Comparator Glucose Values (mg/dL) | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | <40 | 40-60 | 61-80 | 81-120 | 121-160 | 161-200 | 201-250 | 251-300 | 301-350 | 351-400 | >400 |
| **<40** | 2 66.7% | 24 8.5% | 38 2.7% | 5 0.4% | --- | --- | --- | --- | --- | --- | --- |
| **40-60** | 1 33.3% | 156 55.3% | 143 10.2% | 15 1.1% | 4 0.3% | --- | --- | --- | --- | --- | --- |
| **61-80** | --- | 98 34.8% | 894 63.8% | 102 7.3% | 11 0.9% | 2 0.2% | --- | --- | --- | --- | --- |
| **81-120** | --- | 4 1.4% | 327 23.3% | 1,118 79.9% | 159 12.6% | 3 0.3% | --- | --- | --- | --- | --- |
| **121-160** | --- | --- | --- | 159 11.4% | 945 74.7% | 228 24.0% | 16 1.9% | --- | --- | --- | --- |
| **161-200** | --- | --- | --- | --- | 146 11.5% | 611 64.4% | 186 21.6% | 10 1.6% | --- | --- | --- |
| **201-250** | --- | --- | --- | --- | --- | 105 11.1% | 593 68.9% | 185 30.4% | 13 1.3% | --- | --- |
| **251-300** | --- | --- | --- | --- | --- | --- | 66 7.7% | 353 58.1% | 332 33.3% | 4 1.0% | --- |
| **301-350** | --- | --- | --- | --- | --- | --- | --- | 59 9.7% | 589 59.0% | 136 34.3% | --- |
| **351-400** | --- | --- | --- | --- | --- | --- | --- | 1 0.2% | 63 6.3% | 235 59.3% | 30 55.6% |
| **>400** | --- | --- | --- | --- | --- | --- | --- | --- | 1 0.1% | 21 5.3% | 24 44.4% |
| **Total** | 3 | 282 | 1,402 | 1,399 | 1,265 | 949 | 861 | 608 | 998 | 396 | 54 |
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## Trend Accuracy
Adult performance was previously established in K234070.
Trend accuracy describes the accuracy of the sensor during times of rapidly changing glucose and is characterized by slopes, such as from > 2 mg/dL/min to < -2 mg/dL/min. Trend accuracy was assessed by the concurrence rate of the glucose rate of change (changes in mg/dL of glucose per minute) determined by the iCGM values and the corresponding comparator values for each iCGM-comparator measurement pair.
### Trend Accuracy Between iCGM and Comparator - Pediatrics 7-17 YO Arm (N=122)
| iCGM Rate Range (mg/dL/min) N (Row %) | Comparator Rate Range (mg/dL/min) | | | | | | Number of Paired iCGM-Comparator (Row N) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | <-2 | [-2,-1) | [-1,-0) | [0,1] | (1,2] | >2 | |
| **<-2** | 65 (44.2%) | 47 (32.0%) | 26 (17.7%) | 7 (4.8%) | 2 (1.4%) | 0 (0.0%) | 147 |
| **[-2,-1)** | 49 (6.5%) | 397 (52.4%) | 265 (35.0%) | 38 (5.0%) | 7 (0.9%) | 1 (0.1%) | 757 |
| **[-1,0)** | 19 (0.7%) | 251 (8.8%) | 1,989 (70.0%) | 540 (19.0%) | 33 (1.2%) | 10 (0.4%) | 2,842 |
| **[0,1]** | 8 (0.3%) | 37 (1.6%) | 525 (22.9%) | 1,467 (64.1%) | 224 (9.8%) | 29 (1.3%) | 2,290 |
| **(1,2]** | 0 (0.0%) | 3 (0.4%) | 44 (6.2%) | 230 (32.4%) | 340 (48.0) | 92 (13.0) | 709 |
| **>2** | 0 (0.0%) | 5 (1.3%) | 12 (3.1%) | 34 (8.8%) | 112 (29.1%) | 222 (57.7%) | 385 |
| **Number of Paired iCGM-Comparator (Column N)** | 141 | 740 | 2,861 | 2,316 | 718 | 354 | 7,130 |
Note: RoC was calculated using comparator data with consecutive measurements greater than 5 minutes.
### Agreement when iCGM Reads “Below 55 mg/dL” or “Above 350 mg/dL”
The Stelo Glucose Biosensor System reports glucose readings between 55 and 350 mg/dL. When the system determines the sensor reading is below 55 mg/dL, it displays “Below 55 mg/dL” on the mobile app. When the system determines the sensor reading is above 350 mg/dL, it displays “Above 350 mg/dL” on the mobile app. Because the system does not display glucose values below 55 mg/dL or above 350 mg/dL, the comparisons to the actual blood glucose levels (as determined by the comparator) when the biosensor value is classified as “Below 55 mg/dL” or “Above 350 mg/dL” are evaluated separately. The cumulative percentages of when the comparator values were less than certain glucose values (for “Below 55 mg/dL”) and when
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comparator values were greater than certain glucose values (for “Above 350 mg/dL”) are presented in the table below.
# **Distribution of Comparator for iCGM Readings 'Below 55 mg/dL ' or 'Above 350 mg/dL' - Pediatrics 7-17 YO Arm (N=122)**
| iCGM Readings | iCGM-Comparator Pairs | Comparator (mg/dL) | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | | <55 | <60 | <70 | <80 | ≥80 | |
| “Below 55 mg/dL” | n | 47 | 90 | 158 | 195 | 18 | 213 |
| | Cumulative Percent | 22 | 42 | 74 | 92 | 8 | |
| | | | | | | | |
| iCGM Readings | iCGM-Comparator Pairs | >350 | >320 | >280 | >250 | ≤250 | Total |
| “Above 350 mg/dL” | n | 310 | 364 | 375 | 375 | 0 | 375 |
| | Cumulative Percent | 83 | 97 | 100 | 100 | 0 | |
To reflect the expanded glucose display range from 70-250 mg/dL to 55-350 mg/dL, the updated analysis is also provided for adults below based on the adult pivotal study from K234070 conducted on the predicate.
# **Distribution of Comparator for iCGM Readings 'Below 55 mg/dL ' or 'Above 350 mg/dL' - Adults (N=130)**
| iCGM Readings | iCGM-Comparator Pairs | Comparator (mg/dL) | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | | <55 | <60 | <70 | <80 | ≥80 | |
| “Below 55 mg/dL” | n | 105 | 196 | 297 | 328 | 9 | 337 |
| | Cumulative Percent | 31 | 58 | 88 | 97 | 3 | |
| | | | | | | | |
| iCGM Readings | iCGM-Comparator Pairs | >350 | >320 | >280 | >250 | ≤250 | Total |
| “Above 350 mg/dL” | n | 267 | 383 | 396 | 396 | 0 | 396 |
| | Cumulative Percent | 67 | 97 | 100 | 100 | 0 | |
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## Sensor Stability
Adult performance was previously established in K234070.
Sensor stability below describes the pediatric performance over sensor wear day 1-10.5. Pediatric performance was estimated by calculating the percentage of iCGM 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 by clinic session day (Day 1, 2, 4, 7, 10, and 10.5) of the System lifecycle. The mean of the absolute relative difference was evaluated over the sensor life within the measuring range.
Sensor accuracy for pediatrics (ages 2-17) on days 11 to 15 has not been directly assessed. However, based on the design of the Stelo Glucose Biosensor System and available performance data from the G7 10-Day and Stelo systems, it is reasonable to expect that pediatric sensor accuracy may be comparable to adult sensor accuracy.
### Accuracy of iCGM vs Comparator by Clinic Session Day - Pediatrics 7-17 YO Arm (N=122)
| Clinic Day | Matched Pairs (n) | %15/15 (%) | %20/20 (%) | %30/30 (%) | %40/40 (%) | MARD (%) |
| --- | --- | --- | --- | --- | --- | --- |
| Day 1 | 1,745 | 74.8 | 88.1 | 95.8 | 97.7 | 11.1 |
| Day 2 | 1,654 | 86.9 | 95.4 | 98.9 | 99.5 | 7.9 |
| Day 4 | 1,772 | 93.1 | 98.0 | 99.8 | 100.0 | 6.8 |
| Day 7 | 1,577 | 95.9 | 99.0 | 99.9 | 100.0 | 6.6 |
| Day 10 | 671 | 95.1 | 98.2 | 100.0 | 100.0 | 6.5 |
| Day 10.5 | 683 | 89.9 | 93.9 | 98.0 | 99.9 | 7.4 |
| Overall | 8,102 | 88.3 | 95.2 | 98.6 | 99.4 | 7.9 |
## Sensor Life
Adult performance was previously established in K234070.
In the reprocessed clinical study, a total of 149 sensors worn on the arm by pediatric subjects (ages 2-17) were evaluated to determine the percentage of sensors that lasted through sensor wear days 1-10. Of the 149 Sensors, 76.2% lasted until day 10. 24 Sensors (14.1%) had 'early sensor shut-off' (ESS), which is when a sensor automatically ends a sensor session as a result of self-diagnostics. 20 ESS failures were due to progressive sensor decline (PSD), which is a failure attributable to algorithm design. Survival rates were calculated using the Kaplan Meier method.
### Summary of System Survival by Day - Pediatrics 2-17 YO Arm (N Subject = 146)
| Day of wear | Number of sensors (N=149) | Survival rate (%) |
| --- | --- | --- |
| 1 | 141 | 94.6 |
| 2 | 140 | 94.6 |
| 3 | 138 | 93.3 |
| 4 | 137 | 93.3 |
| 5 | 135 | 91.9 |
| 6 | 134 | 91.2 |
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| 7 | 130 | 88.5 |
| --- | --- | --- |
| 8 | 125 | 85.1 |
| 9 | 118 | 80.3 |
| 10 | 106 | 76.2 |
A total of 16 sensors worn on the buttocks by pediatric subjects (ages 2-6) were evaluated to determine the percentage of sensors that lasted through sensor wear days 1-10. Of the 16 Sensors, 56.3% lasted until day 10. 7 Sensors (43.8%) had ESS, 4 of which were due to PSD. Survival rates were calculated using the Kaplan Meier method.
#### **Summary of System Survival by Day - Pediatrics 2-6 YO Buttocks (N Subject = 16)**
| Day of wear | Number of sensors (N=16) | Survival rate (%) |
| --- | --- | --- |
| 1 | 15 | 93.8 |
| 2 | 14 | 87.5 |
| 3 | 14 | 87.5 |
| 4 | 14 | 87.5 |
| 5 | 14 | 87.5 |
| 6 | 14 | 87.5 |
| 7 | 12 | 75.0 |
| 8 | 11 | 68.8 |
| 9 | 11 | 68.8 |
| 10 | 9 | 56.3 |
However, the clinical study from K213919 that was reprocessed with the subject device algorithm utilized a different sensor adhesive patch and overpatch than the subject device. Therefore, algorithm-driven shutoff represents the likely predominant factor in the survival analyses above for the subject device. While pediatric sensor survival has not been assessed for the Stelo System for Days 11-15, based on the design of the Stelo Glucose Biosensor System and available performance data from the G7 10-day and Stelo systems, it is reasonable to expect that pediatric sensor survival is likely lower than adult survival.
#### **Data Capture Rate**
The data capture rate characterizes the reliability of the communication between components of the system. The following table describes the data availability rate as the percentage of readings expected to be calculated throughout sensor wear days 1-10 for pediatrics ages 2-17 (arm only) based on information collected in the reprocessed clinical study from K213919.
#### **Data Availability Rate By Wear Day - Pediatrics 2-17 YO Arm (N=145)**
| Wear Day | Number of Sensors | Data Availability Rate(%) |
| --- | --- | --- |
| 1 | 145 | 99.5 |
| 2 | 141 | 99.8 |
| 3 | 140 | 99.8 |
| 4 | 138 | 99.6 |
| 5 | 137 | 99.3 |
| 6 | 135 | 99.2 |
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| 7 | 134 | 99.2 |
| --- | --- | --- |
| 8 | 130 | 98.7 |
| 9 | 125 | 96.9 |
| 10 | 118 | 96.9 |
| Overall (Day 10) | 145 | 99.0 |
# **Data Availability Rate by Wear Day - Pediatrics 2-6 YO Buttocks (N=16)**
| Wear Day | Number of Sensors | Data Availability Rate(%) |
| --- | --- | --- |
| 1 | 16 | 98.9 |
| 2 | 15 | 98.7 |
| 3 | 14 | 99.7 |
| 4 | 14 | 99.5 |
| 5 | 14 | 99.2 |
| 6 | 14 | 97.9 |
| 7 | 14 | 97.8 |
| 8 | 12 | 98.7 |
| 9 | 11 | 98.2 |
| 10 | 11 | 95.8 |
| Overall (Day 10) | 16 | 98.5 |
# **D Expected Values/Reference Range:**
Not applicable
# **E Other Supportive Instrument Performance Characteristics Data:**
The following supportive performance characteristics were previously established through non-clinical testing performed on previously cleared G7 CGM System reference devices and are applicable to the Stelo Glucose Biosensor System in this 510(k):
- Electrical Safety and Electromagnetic Compatibility (EMC) in K234133 (G7 10-Day DTW) and K243214 (G7 15-Day)
- Wireless Coexistence in K243214 (G7 15-Day)
- Communication Range Testing in K234133 (G7 10-Day DTW)
The following supportive performance characteristics were established through nonclinical testing of the predicate device and are applicable to the Stelo Glucose Biosensor System in this 510(k):
- Biocompatibility
- Chemical/Material Characterization
- Electrical and Mechanical Performance
- Operating Environmental Conditions Testing
- Sterilization Validation
- Packaging Validation
- Interoperability
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The following performance characteristics were verified or validated through studies conducted on the subject device in this 510(k):
#### Software Verification and Validation
Software verification and validation testing was conducted to confirm that the software used in the Stelo Glucose Biosensor System performed in accordance with established specifications, IEC 62304 and FDA guidance document “*Guidance for the Content of Premarket Submissions for Device Software Functions*,” issued June 14, 2023. Evaluation activities included code review, unit, system integration, and system level testing. Results of the executed protocols for the Stelo Glucose Biosensor System are acceptable for its intended use.
#### Cybersecurity
Dexcom provided cybersecurity risk management documentation for the Stelo Glucose Biosensor System that includes analysis of confidentiality, integrity, and availability for data, information, and software related to the device. 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. In addition, Dexcom has controls and processes in place to ensure continued support for keeping the device secure and to ensure that the device firmware, software and components are malware free. Additional controls are also in place in manufacturing through distribution to ensure that the medical device firmware and software are malware free from point of origin to the hands of the end user.
#### Human Factors
The user interface of the Stelo Glucose Biosensor System has been found to support that the device is substantially equivalent to the predicate device for the intended users, uses, and use environments. Human factors validation studies provided in K234070 and K213919 are applicable to the Stelo Glucose Biosensor System in this 510(k).
#### Shelf-Life
Shelf-life testing was performed to evaluate the stability of the Stelo Glucose Sensing Subsystem under real-time anticipated storage conditions and supported its useful life to be up to 18 months. The test results for the Stelo Glucose Sensing Subsystem met specifications.
### **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.
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