Signos Glucose Monitoring System

K250106 · Signos, Inc. · SAF · Mar 21, 2025 · Clinical Chemistry

Device Facts

• Record ID: K250106
• Device Name: Signos Glucose Monitoring System
• Applicant: Signos, Inc.
• Product Code: SAF · Clinical Chemistry
• Decision Date: Mar 21, 2025
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1355
• Device Class: Class 2
• Attributes: Software as a Medical Device

Indications for Use

The Signos Glucose Monitoring System is an over-the-counter (OTC) mobile device application that receives data from an integrated Continuous Glucose Monitor (iCGM) sensor and is intended to continuously measure, record, analyze, and display glucose values in people 18 years and older not on insulin. The Signos System helps to identify normal (euglycemic) and low or high (dysglycemic) glucose levels. The Signos System may also help the user better understand how lifestyle and behavior modification, including diet and exercise, impact glucose excursions. This information may be useful in helping users to maintain a healthy weight. The user is not intended to take medical action based on the device output without consultation with a qualified healthcare professional.

Device Story

Signos Glucose Monitoring System is a mobile application paired via Bluetooth with an interoperable Continuous Glucose Monitor (iCGM). It functions as a primary display for the iCGM, receiving and displaying glucose readings and historic trends every 15 minutes. The system supports data backfilling and grace periods defined by the iCGM. Used in home settings by patients over 18 not on insulin, the app provides graphs, text, and notifications to illustrate glucose trends. Users utilize this information to observe how diet and exercise impact glucose levels, assisting in weight management and maintenance of a euglycemic state. The device does not perform medical diagnosis or treatment; users are instructed to consult healthcare professionals before taking medical action based on output.

Clinical Evidence

No clinical data. Performance supported by human factors study (n=18) confirming user ability to onboard, pair sensors, and interpret app screens. Software verification and validation conducted per IEC 62304. Cybersecurity risk management performed per FDA guidance.

Technological Characteristics

Mobile application software; operates on Android or iOS hardware. Connectivity via Bluetooth. Displays glucose data (70-250 mg/dL) received from an interoperable iCGM. Uses the same sensor as the predicate. Software design includes data display, trend analysis, and user notifications. No sensor calibration performed by the application.

Indications for Use

Indicated for people 18 years and older not on insulin to continuously measure, record, analyze, and display glucose values, detect euglycemic/dysglycemic levels, and understand lifestyle/behavior impacts on glucose excursions for weight management. 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

• Stelo Glucose Biosensor System (K234070)

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

K250106

B Applicant

Signos, Inc.

C Proprietary and Established Names

Signos Glucose Monitoring 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 Type of Test:

Quantitative, amperometric assay (Glucose Oxidase)

## III Intended Use/Indications for Use:

A Intended Use(s):

See Indications for Use below.

Food and Drug Administration

10903 New Hampshire Avenue

Silver Spring, MD 20993-0002

www.fda.gov

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B Indication(s) for Use:

The Signos Glucose Monitoring System is an over-the-counter (OTC) mobile device application that receives data from an integrated Continuous Glucose Monitor (iCGM) sensor and is intended to continuously measure, record, analyze, and display glucose values in people 18 years and older not on insulin. The Signos System helps to identify normal (euglycemic) and low or high (dysglycemic) glucose levels. The Signos System may also help the user better understand how lifestyle and behavior modification, including diet and exercise, impact glucose excursions. This information may be useful in helping users to maintain a healthy weight.

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

IV Device/System Characteristics:

A Device Description:

Signos Glucose Monitoring System is a mobile device application that receives data from the Dexcom Stelo Biosensor iCGM and used to help people better understand their impact on their glucose results and how those glucose results impact other areas of their health.

The Signos Glucose Monitoring System consists of the smartphone application (on iOS or Android) and is paired with the Dexcom Stelo Glucose Biosensor System (distributed by Signos, Inc. upon payment and activation of the Signos Glucose Monitoring System). The application is obtained by downloading it from an App-Store (e.g. Google Play or Apple Store) and then activated by account setup with Signos, Inc.

Once activated, the Signos Glucose Monitoring System application functions as a primary display for a paired, off-the-shelf, Dexcom Stelo iCGM (K234070) by showing the user's glucose reading along with a historic trend. The Signos Glucose Monitoring System is not intended to be used by people on insulin.

The Signos Glucose Monitoring System includes several algorithms that analyze glucose values. These algorithms are variously intended to help identify euglycemic and dysglycemic glucose levels, and to help users better understand how lifestyle and behavior modification, including diet and exercise, impact glucose excursions. These algorithms are not intended to aid in the management of any disease.

B Instrument Description Information:

1. Instrument Name:

Signos Glucose Monitoring System

2. Specimen Identification:

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Not applicable

3. Specimen Sampling and Handling:

Not applicable

4. Calibration:

Not applicable to subject device. The Stelo Glucose Biosensor System (K234070) is factory calibrated.

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.

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): | K250106 | K234070 |
| --- | --- | --- |
| Device Trade Name | Signos Glucose Monitoring System | Stelo Glucose Biosensor System |
| General Device Characteristic Similarities | | |
| Use Setting | Home use | Same |
| Intended Use Population | Persons who are not on insulin therapy age 18 years and older | Same |
| Type of Use | Over-the-counter use | Same |
| Displayed Range | 70-250 mg/dL | Same |

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| Display Device Update Interval | Every 15 minutes | Same |
| --- | --- | --- |
| Glucose Alerts and Alarms | None | Same |
| General Device Characteristic Differences | | |
| Sensor | Not included in clearance. Uses same sensor as cleared in predicate | Included in clearance. |
| Principle of Operation | Mobile device application displaying data
Uses same sensor as cleared in predicate. | Mobile device application displaying data and biosensor:
Amperometric measurement of current proportional to glucose concentration in interstitial fluid via glucose oxidase chemical reaction |

VI Standards/Guidance Documents Referenced:

None

VII Performance Characteristics (if/when applicable):

A Analytical Performance:

1. Precision/Reproducibility:
Previously established in K234070.

2. Linearity:
Previously established in K234070.

3. Analytical Specificity/Interference:
Previously established in K234070.

4. Accuracy (Instrument):
Not applicable.

5. Carry-Over:

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Not Applicable.

## B Other Supportive Instrument Performance Characteristics Data:

The following supportive performance characteristics were verified or validated through studies conducted on the subject device.

### Human Factors

Eighteen participants enrolled in the study. Before entering the study session, participants completed a Health Assessment Questionnaire (HAQ). Fifteen of eighteen participants correctly self-selected as intended users. Participants representing intended users of the Product completed in-App onboarding, set-up the biosensor and paired it, logged meal and exercise information, and reviewed various App screens and answered questions about them.

### 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 “Guidance for the Content of Premarket Submissions for Device Software Functions,” June 14, 2023. The test results for the Signos Glucose Monitoring System met acceptance criteria and are acceptable for their intended use.

### Cybersecurity

Signos has provided cybersecurity risk management documentation for the Signos Glucose Monitoring System that includes analysis of confidentiality, integrity, and availability for data, information and software related to the Signos Glucose Monitoring System in accordance with the FDA Guidance Cybersecurity in Medical Devices: Quality System Considerations and Content of Premarket Submissions” (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. In addition, Signos 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.

## 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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