The Carbon Monoxide Breath Sensor System (COBSS) is a breath carbon monoxide monitor intended for single-user use by cigarette smokers in smoking cessation programs to inform the user about how breath carbon monoxide levels are affected by smoking behavior. The device is not intended to be used with other inhaled products.

Device Description

The Carbon Monoxide Breath Sensor System (COBSS) is a breath carbon monoxide ("CO") monitor intended for single-user over-the-counter ("OTC") use by smokers in smoking cessation programs. The COBSS is a portable, battery-powered device that is composed of the following:

. CO Breath Sensor. A personal mobile breath sensor capable of measuring the level of CO in exhaled breath.
. Breath Sensor App. A smart phone app which displays the exhaled breath CO value to the user.

The CO Breath Sensor pairs to the Breath Sensor Application ("BSA") on the smartphone via low-energy Bluetooth. Once paired, the CO Breath Sensor communicates exclusively with the user's phone and is invisible to other devices. The primary screen for the BSA is the CO Log where the most recent exhaled breath CO value in parts-per-million ("ppm") is displayed at the top of the screen. The CO measurements are color coded according to the CO level, and the length of the bar is associated with the ppm value to graphically show the user their relative levels of exhaled breath CO throughout the day and between days.

AI/ML Overview

Here's an analysis of the acceptance criteria and the study that proves the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly list acceptance criteria in a quantitative table format. However, it implies acceptance through the comparative performance study results and the conclusion of substantial equivalence. Based on the provided text, the implied acceptance criteria were:

Feature/Metric	Implied Acceptance Criteria (Based on Predicate/Goals)	Reported Device Performance (COBSS)
Accuracy / Correlation with Predicate	Strong correlation to predicate device's CO measurements.	Regression analysis: slope 0.9289, y-intercept -0.0306, correlation coefficient 0.9878, between COBSS and predicate.
Categorical Agreement with Predicate	High agreement between COBSS CO level categories and predicate's CO level categories.	91% (64/70) overall agreement. Green category (0-6 ppm): 95% (18/19); Orange category (7-9 ppm): 71% (5/7); Red category (10+ ppm): 93% (41/44).
Human Factors / Usability by Lay Users	Untrained lay users can operate the device and interpret results correctly and safely.	All participants safely used primary operating functions; no hazard-related use scenarios observed. Risk profile acceptability confirmed.
Sensor Performance (Accuracy, Precision, Linearity, H2 Cross Sensitivity)	Performance comparable to predicate device.	Bench testing confirms sensor performance, including accuracy, precision, linearity, and H2 Cross Sensitivity.
Interfering Gases	Acceptable performance in the presence of specified interfering gases.	Interfering gases testing performed. (Specific performance metrics not detailed, but implied as acceptable for SE).
Shelf Life/Sensor Drift	Acceptable shelf life and sensor drift.	Shelf life/Sensor drift testing performed. (Specific performance metrics not detailed, but implied as acceptable for SE).

2. Sample Size Used for the Test Set and Data Provenance

Sample Size for Test Set: 70 lay users.
Data Provenance: The study was a "prospective, open label, single center design." The participants comprised adult smokers, representative of the intended COBSS user profile. The country of origin of the data is not explicitly stated, but given the FDA submission, it is likely the study was conducted in the US.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Those Experts

The concept of "ground truth" for the test set is slightly different in this context. The study did not establish a ground truth through expert consensus on CO levels. Instead, it used a predicate device (Micro+ Smokerlyzer) administered by trained personnel as the reference standard for comparative performance. The document states that the predicate device was "submitted with guidance by a health care professional trained in the use of the device." The number and specific qualifications of these "health care professionals" are not detailed beyond "trained in the use of the device."

4. Adjudication Method for the Test Set

There was no explicit adjudication method described for the test set in terms of resolving discrepancies between multiple readers or experts. The comparison was primarily between the COBSS used by lay users and the predicate device used by trained personnel.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study as typically defined for imaging diagnostics (comparing multiple readers' interpretations with and without AI assistance on multiple cases) was not conducted. This study focused on the performance of the device itself (both standalone and with lay users) compared to a predicate, and the usability of the device by lay users. It assessed the ability of lay users to use the device without assistance compared to trained personnel using the predicate device.

Effect size of human readers improving with AI vs. without AI assistance: Not applicable, as this was not an MRMC study comparing human performance with and without AI assistance. Instead, it compared the COBSS with untrained lay users to a predicate with trained healthcare professionals.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Yes, a standalone performance component was conducted through bench testing. This testing evaluated:

Sensor performance (accuracy, precision, linearity, H2 Cross Sensitivity)
Interfering Gases
Device Use Testing
Shelf Life/Sensor Drift

These tests evaluate the intrinsic performance of the sensor and device system without human interaction for measurement acquisition or interpretation.

7. Type of Ground Truth Used

The "ground truth" for the comparative performance study was the measurements provided by the predicate device (Micro+ Smokerlyzer) when administered by trained healthcare professionals. This is a form of reference standard comparison against an already cleared and accepted medical device.

8. Sample Size for the Training Set

The document does not provide information on the sample size used for the training set for the COBSS device. This is common for devices of this type where the core technology might be based on established electrochemical sensing, and the "training" may refer more to calibration and validation of the sensor hardware and associated algorithms rather than a conventional machine learning training set with labeled data.

9. How the Ground Truth for the Training Set Was Established

Given the lack of information on a "training set" and its size, how ground truth for it was established is also not provided. For sensor-based devices, "ground truth" during development often involves:

Controlled gas mixtures with known CO concentrations.
Comparison against highly accurate laboratory reference instruments.
Characterization of sensor response across its specified range and environmental conditions.

The document mentions "bench testing" which would likely involve such methods for calibrating and validating the sensor's fundamental performance characteristics. However, explicit details on training data ground truth are absent.

Summary

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002 September 29, 2017

CARROT SENSE, INC. C/O JONATHAN KAHAN PARTNER 555 THIRTEENTH STREET NW WASHINGTON DC 20004

Re: K171408

Trade/Device Name: Carbon Monoxide Breath Sensor System (COBSS) Regulation Number: 21 CFR 868.1430 Regulation Name: Carbon monoxide gas analyzer Regulatory Class: II Product Code: CCJ Dated: August 30, 2017 Received: August 30, 2017

Dear Jonathan Kahan:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

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If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely yours,

Kellie B. Kelm -S

for Courtney H. Lias, Ph.D. Director Division of Chemistry and Toxicology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health

Enclosure

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Form Approved: OMB No. 0910-0120
Expiration Date: 06/30/2020
See PRA Statement below.

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration

Indications for Use

510(k) Number (if known)	K171408
Device Name	Carbon Monoxide Breath Sensor System (COBSS)
Indications for Use (Describe)	The Carbon Monoxide Breath Sensor System (COBSS) is a breath carbon monoxide monitor intended for single-user use by cigarette smokers in smoking cessation programs to inform the user about how breath carbon monoxide levels are affected by smoking behavior. The device is not intended to be used with other inhaled products.

Type of Use (Select one or both, as applicable)	Prescription Use (Part 21 CFR 801 Subpart D) Over-The-Counter Use (21 CFR 801 Subpart C)
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K171408

510(k) SUMMARY

Carrot Sense's Carbon Monoxide Breath Sensor System (COBSS)

Submitter

Company:	Carrot Sense, Inc.
Address:	1600 Seaport Blvd, Suite 150Redwood City, CA 94063
Phone:	(650) 520-3259
Contact Person:	Daniel J Balbierz
Date Prepared:	September 27, 2017

Subject Device

Name of Device:	Carbon Monoxide Breath Sensor System (COBSS)
Classification Name:	Carbon monoxide gas analyzer
Regulation:	21 C.F.R. § 868.1430
Regulatory Class:	Class II
Product Code:	CCJ

Predicate Device

Company:	Bedfont Scientific LTD
Device Name:	Micro+ Smokerlyzer
510(k) Number:	K082315
Regulation:	868.1430
Product Codes:	CCJ

Device Description

. CO Breath Sensor. A personal mobile breath sensor capable of measuring the level of CO in exhaled breath.
. Breath Sensor App. A smart phone app which displays the exhaled breath CO value to the user.

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CO levels in exhaled breath of smokers correlate closely with smoking behavior, i.e., intensity, frequency, and amount. Simply put, the more a person smokes, the higher their exhaled breath CO levels tend to be. Exhaled breath CO readings can inform the user about how breath carbon monoxide levels are affected by smoking behavior.

Intended Use / Indications for Use

The Carbon Monoxide Breath Sensor System (COBSS) is a breath carbon monoxide monitor intended for single user use by cigarette smokers in smoking cessation programs to inform the user about how breath carbon monoxide levels are affected by smoking behavior. The device is not intended to be used with other inhaled products.

Substantial Equivalence

The COBSS is substantially equivalent to Bedfont Scientific's Micro+ Smokerlyzer ("Smokerlyzer") cleared under 510(k) number K082315. Both devices have the same intended use of measuring breath CO levels of smokers in smoking cessation programs. Specifically, both the subject and the predicate devices provide breath CO measurements to inform the user about how breath carbon monoxide levels are affected by smoking behavior. The COBSS' labeling provides a clear understanding of the CO measurements, appropriate precautions, and warnings. A combined human factors and comparative study demonstrated that lay users were able to adequately use the COBSS and to understand the CO measurements.

In addition, the COBSS has similar technological characteristics as the predicate device. Both are portable, battery powered devices that use electrochemical sensors to non-invasively monitor CO levels. The COBSS provides the CO measurements in a smartphone app, while the predicate uses a touch screen display. However, these minor differences in technological characteristics do not present any different issues of safety or effectiveness. In addition, analytical bench testing and the combined performance and human factors study demonstrated substantially equivalent performance between the subject and the predicate devices. Thus, the COBSS is substantially equivalent to the predicate device.

A substantial equivalence table summarizing the similarities and differences between the COBSS and the predicate device is provided in Table 1.

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Table 1 – Comparison of Substantial Equivalence

Similarities
Feature	Subject Device:Carrot Sense'sCOBSS	Predicate Device: BedfontScientific's Micro+Smokerlyzer (K082315)
Intended Use	Intended for single-useruse by cigarette smokersin smoking cessationprograms to inform theuser about how breathcarbon monoxide levelsare affected by smokingbehavior.	Intended for multipatient useby healthcare professionals insmoking cessation programsand as an indicator of CarbonMonoxide poisoning inhealthcare environments.
SensorTechnology	Same	Electrochemical Sensor
Sensor Drift	Same	<5% per annum
H2 CrossSensitivity	Same	<6%

Differences

Feature	Subject Device: CarrotSense's COBSS	Predicate Device: BedfontScientific's Micro+Smokerlyzer (K082315)
Environmentof Use	Over the counter, home	Prescription use only,healthcare
DesignFeatures	• Non-invasivelymeasures CO inexhaled breath• Hand-held batterypowered• Visual and audiblealarms	• Non-invasively measuresCO in exhaled breath• Hand-held battery powered• Visual and audible alarms• Touch screen interface• No smartphone app
PowerSource	Rechargeable lithium ionbattery	4.5V, 3 x AA/LR6 type battery
CO MeasuringRange	0 – 100 ppm	0 - 250 ppm
InterferingGases	Hydrogen	Hydrogen, Nitric Oxide,and Ethylene

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Bench Testing

The following summarizes the bench testing completed for the Carbon Monoxide Breath Sensor System:

. Sensor performance, including accuracy, precision, linearity, and H2 Cross Sensitivity
. Interfering Gases
Device Use Testing ●
Shelf Life/Sensor Drift

Combined Human Factors and Comparative Performance Study

Carrot Sense conducted a combined human factors and comparative performance study to evaluate the following:

· Human Factors: Assess whether an untrained lay user group (representative of intended users) can operate the device and interpret the results correctly using the device labeling.
· Comparative Performance: Assess the correlation between the measured CO levels (in ppm) of the study CO breath sensor (Carrot Sense) submitted by a self-trained user without guidance by study personnel and the predicate CO breath sensor (Smokerlyzer) submitted with guidance by a health care professional trained in the use of the device.

The study was a prospective, open label, single center design and enrolled 70 lay users. Study participants comprised adult smokers, who represent the intended COBSS user profile. The study included two user groups (ages 18-49 years and 50-80 years). Study subjects participated in 60-90 minute study sessions that consisted of an introduction, simulated use, performance paired breath samples, user documentation assessment and subjective feedback and rating scales.

For the comparative performance portion of the study, the measurement of CO in exhaled breath by a lay user using COBSS without assistance was comparable to measurements obtained from the predicate device administered by trained personnel. On regression analysis, the 70 paired measurements of CO produced a line with a slope of 0.9289, a y-intercept of -0.0306 and a correlation coefficient of 0.9878. COBSS CO measurements agreed with the predicate device's category 91% (64/70) of the time. The COBSS CO level category agreed with the predicate's CO level category in 18/19 (95%) paired samples for the green category (0-6 ppm), 5/7 (71%) for the orange category (7-9 ppm), and 41/44 (93%) for the red category (10 ppm or greater).The human factors/usability portion of the study demonstrated that the device is safe and effective for the intended users, its intended uses, and use environments. All participants, overall, were observed to safely use all primary operating functions. There were no instances of close calls or observed hazard-related use scenarios that could have resulted in significant patient or user harm. Based on both objective and subjective input, the risk profile acceptability of the device was confirmed.

Overall, the combined human factors and comparative performance study demonstrated that lay users were able to use the COBSS safely and effectively for its intended use, and that the COBSS performance was acceptable when compared to the predicate device.

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Conclusion

The COBSS is substantially equivalent to the predicate Smokerlyzer. Both devices have the same intended uses and similar indications, technological characteristics, and principles of operation. The differences in OTC indication do not alter the intended use of the device as a breath CO monitor for smoking cessation programs. In addition, minor technological differences between the COBSS and its predicate device do not raise different questions of safety or effectiveness. Bench testing and a combined human factors and comparative study demonstrated substantially equivalence performance. Furthermore, the study demonstrated that lay users were able to adequately use the COBSS and understand the CO measurements. Thus, the COBSS is substantially equivalent to the predicate device.

Regulation Number and Section

§ 868.1430 Carbon monoxide gas analyzer.

(a)
Identification. A carbon monoxide gas analyzer is a device intended to measure the concentration of carbon monoxide in a gas mixture to aid in determining the patient's ventilatory status. The device may use techniques such as infrared absorption or gas chromatography.(b)
Classification. Class II (performance standards).