Carbon Monoxide Breath Sensor System (COBSS)
Device Facts
| Record ID | K171408 |
|---|---|
| Device Name | Carbon Monoxide Breath Sensor System (COBSS) |
| Applicant | Carrot Sense, Inc. |
| Product Code | CCJ · Anesthesiology |
| Decision Date | Sep 29, 2017 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 868.1430 |
| Device Class | Class 2 |
Intended 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.
Device Story
Portable, battery-powered breath CO monitor for single-user, over-the-counter use. Device samples exhaled breath via electrochemical sensors; microprocessor converts sensor current to CO concentration. System includes a hand-held sensor and a smartphone application (Breath Sensor Application) connected via Bluetooth. App displays CO levels in ppm and color-coded bars (green 0-6 ppm, orange 7-9 ppm, red ≥10 ppm) to track smoking behavior. Device includes a second electrochemical sensor to detect and adjust for hydrogen gas interference. Users exhale into the device; results are displayed on the smartphone screen. No user recalibration; device is factory-calibrated. Provides visual feedback to inform users about the impact of smoking on CO levels.
Clinical Evidence
Prospective, open-label, single-center study with 70 adult smokers (ages 18-80). Evaluated human factors and comparative performance against the predicate device. Regression analysis of 70 paired samples showed a slope of 0.9289, y-intercept of -0.0306, and correlation coefficient of 0.9878. COBSS agreed with predicate CO level categories in 91% (64/70) of samples. Human factors testing confirmed lay users could safely operate the device and interpret results without assistance. No hazard-related use scenarios were observed.
Technological Characteristics
Portable, battery-powered (rechargeable lithium-ion) device. Uses an electrochemical sensor for CO detection. Connectivity via low-energy Bluetooth to a smartphone app. Measurement range: 0–100 ppm. Sensor drift <5% per annum; H2 cross-sensitivity <6%.
Indications for Use
Indicated for cigarette smokers in smoking cessation programs to monitor breath carbon monoxide levels. Not for use by multiple persons, for suspected carbon monoxide poisoning, for suspected fire smoke inhalation, or for point-of-care clinical settings.
Regulatory Classification
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.
Predicate Devices
- Micro+ Smokerlyzer (K082315)
Related Devices
- K201206 — Pivot Breath Sensor · Carrot, Inc. · Jun 30, 2021
- K211918 — iCOquit® Smokerlyzer® · Bedfont Scientific, Ltd. · Dec 21, 2021
Submission Summary (Full Text)
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY INSTRUMENT ONLY TEMPLATE
A. 510(k) Number:
k171408
B. Purpose for Submission:
New device
C. Manufacturer and Instrument Name:
Carrot Sense, Inc. Carbon Monoxide Breath Sensor System (COBSS)
D. Type of Test or Tests Performed:
Quantitative (electrochemical sensor)
E. System Descriptions:
1. Device Description:
The Carbon Monoxide Breath Sensor System (COBSS) is a breath carbon monoxide (CO) monitor for single person use. The COBSS is a portable, battery-powered device that is composed of the following:
- A hand-held CO breath sensor that uses electrochemical technology to sample the gas from a user’s exhaled breath, and a microprocessor to convert the output from the sensor to a CO concentration.
- A mobile phone (smartphone) software application (the Breath Sensor Application (BSA)) which displays the exhaled breath CO value to the user.
The Carbon Monoxide Breath Sensor System (COBSS) pairs to the BSA on the smartphone via low-energy Bluetooth. The most recent exhaled breath CO value is displayed at the top of the smartphone screen with several visual characteristics for user interpretation: results are displayed in parts-per-million (“ppm”), and as a color color coded bar that is related to the ppm value: green (0 – 6 ppm CO), orange (7 – 9 ppm CO), or red (≥ 10 ppm CO). The graphical display shows the user their relative levels of exhaled breath CO throughout the day and between days.
2. Principle of Operation:
The Carbon Monoxide Breath Sensor System (COBSS) uses electrochemical sensors to quantify the CO level in the breath. The sensor chemically reacts with CO, creating a small current which is measured by device circuitry. The CO Breath Sensor also employs a second electrochemical sensor to detect hydrogen gas, and uses this value to adjust the
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CO sensor measurement for signal due to hydrogen in the breath.
3. **Modes of Operation:**
Does the applicant’s device contain the ability to transmit data to a computer, webserver, or mobile device?
☑ Yes ☐ or No
Does the applicant’s device transmit data to a computer, webserver, or mobile device using wireless transmission?
☑ Yes ☐ or No
4. **Specimen Identification:**
There is no mechanism to identify the specimen.
5. **Specimen Sampling and Handling:**
The user provides a breath sample by exhaling into the device.
6. **Calibration:**
The device is calibrated by the manufacturer. There is no option for recalibration by the user.
7. **Quality Control:**
External quality controls are not supplied with this device.
8. **Software:**
FDA has reviewed applicant’s Hazard Analysis and Software Development processes for this line of product types:
☑ Yes ☐ or No
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F. Regulatory Information:
| Analyte | Product Code | Classification | Regulation Section | Panel |
| --- | --- | --- | --- | --- |
| Carbon Monoxide | CCJ | Class II | 868.1430 Carbon monoxide gas analyzer | Anesthesiology (73) |
G. Intended Use:
1. Indication(s) 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.
2. Special Conditions for Use Statement(s):
For over the counter use.
Not for multiple person use.
Not for use in cases of suspected carbon monoxide poisoning.
Not for use in cases of suspected fire smoke inhalation.
Not for point of care use in clinical settings.
H. Substantial Equivalence Information:
1. Predicate Device Name(s) and 510(k) numbers:
Bedfont Scientific LTD. Micro+ Smokerlyzer (k082315)
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2. Comparison with Predicate Device:
Similarities
| Feature | Subject Device: Carrot Sense COBSS | Predicate Device: Bedfont Scientific Micro+ Smokerlyzer (k082315) |
| --- | --- | --- |
| Intended Use | 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. | Intended for multipatient use by healthcare professionals in smoking cessation programs and as an indicator of Carbon Monoxide poisoning in healthcare environments. |
| Sensor Technology | Same | Electrochemical Sensor |
| Sensor Drift | Same | <5% per annum |
| H2 Cross Sensitivity | Same | <6% |
Differences
| Feature | Subject Device: Carrot Sense COBSS | Predicate Device: Bedfont Scientific Micro+ Smokerlyzer (k082315) |
| --- | --- | --- |
| Environment of Use | Over the counter | Prescription use only |
| Design Features | • Non-invasively measures CO in exhaled breath
• Hand-held battery powered
• Visual and audible alarms
• Connects with smartphone through Bluetooth
• App for iOS and Android operating systems | • Non-invasively measures CO in exhaled breath
• Hand-held battery powered
• Visual and audible alarms
• Touch screen interface
• No smartphone app |
| Power Source | Rechargeable lithium ion battery | 4.5V, 3 x AA/LR6 type battery |
| CO Measuring Range | 0 – 100 ppm | 0 – 250 ppm |
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I. Special Control/Guidance Document Referenced (if applicable):
| Stds No. | Standards Organization | Standards Title | Date |
| --- | --- | --- | --- |
| 60601-1 | IEC | Medical Electrical Equipment - Part 1: General Requirements for Basic Safety and Essential Performance | 2005/(R) 2012 and A1:2012, C1:2009/(R)2012 and A2:2010/(R)2012 |
| 60601-1-2 | IEC | Medical Electrical Equipment - Part 1-2: General Requirements for Basic Safety and Essential Performance - Collateral Standard: Electromagnetic Disturbances - Requirements and Tests | 2014-02 |
| 60601-1-6 | IEC | Medical Electrical Equipment - Part 1-6: General Requirements for Basic Safety and Essential Performance - Collateral Standard: Usability | 2013-10 |
| 60601-1-11 | IEC | 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 | 2010-04 |
| 10993-1 | ISO | Biological evaluation of medical devices Part 1: Evaluation and testing within a risk management process | 2009 |
| 62366-1 | IEC | Medical devices – Part 1: Application of usability engineering to medical devices | 2015-02 |
| 3A | ISTA | General Simulation Performance Test Procedure Packaged-Products for Parcel Delivery System Shipment 70 | 2008 |
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| Stds No. | Standards Organization | Standards Title | Date |
| --- | --- | --- | --- |
| | | kg (150 lb) or Less | |
| 62304 | AAMI / ANSI / IEC | Medical Device Software - Software Life Cycle Processes | 2006 |
| 14971 | ISO | Medical Devices - Application Of Risk Management To Medical Devices | 2012 |
## J. Performance Characteristics:
### 1. Analytical Performance:
#### a. Accuracy:
The sponsor performed an accuracy study comparing the CO results from 70 lay user study participants who provided breath samples on both the predicate and candidate devices. All of the participants self-reported smoking 2 or more cigarettes per day. There were 38 male and 32 female study participants, with 39 participants in the 18-49 year old age range and 31 participants in the 50-80 year old age range.
Seventy paired CO measurements from the candidate and the predicate device were obtained, and concentrations for the predicate device ranged from 2 to 66 ppm. A regression model was fit using the 70 paired CO measurements from the candidate and the predicate devices that produced a line equation with a slope of 0.9289, a y-intercept of -0.0306 and a correlation coefficient of 0.9878.
Accuracy of the candidate device was also assessed by comparing the concordance between the color categories obtained from the candidate device and the predicate device, and the results are summarized in the following tables.
| Predicate: 19 Green results | | | |
| --- | --- | --- | --- |
| | Green | Orange | Red |
| Candidate | 18 | 1 | 0 |
The discordant candidate result was 7 ppm.
| Predicate: 7 Orange results | | | |
| --- | --- | --- | --- |
| | Green | Orange | Red |
| Candidate | 2 | 5 | 0 |
The discordant candidate results were 4 and 6 ppm.
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| Predicate: 44 Red results | | | |
| --- | --- | --- | --- |
| Candidate | Green | Orange | Red |
| Candidate | 0 | 3 | 41 |
The discordant candidate results were 8, 8, and 9 ppm.
Accuracy within the claimed acceptable temperature range for use was also determined: see section J.1.b
## b. Precision/Reproducibility:
The sponsor evaluated between-run precision using simulated breath samples collected from eleven devices, with three measurements per device for a total of 33 measurements per CO concentration tested. The data was collected by a single operator over two days. Results are summarized below:
| CO Concentration | 0 ppm | 5 ppm | 10 ppm | 20 ppm | 50 ppm | 100 ppm |
| --- | --- | --- | --- | --- | --- | --- |
| mean | 0.5 | 5.8 | 10.8 | 19.8 | 47.9 | 99.0 |
| SD | 0.4 | 0.8 | 0.9 | 1.1 | 2.2 | 5.3 |
| CV(%) | 76.7 | 13.8 | 8.8 | 5.6 | 4.6 | 5.4 |
| low | 0 | 4.7 | 9.5 | 17.5 | 42.7 | 89.3 |
| high | 1.4 | 8.3 | 14.2 | 22.4 | 51.6 | 109.2 |
| n | 33 | 33 | 33 | 33 | 33 | 33 |
The same data was used to calculate repeatability (within-run precision) and the results are summarized below:
| CO Concentration | 0 ppm | | | mean | SD | CV |
| --- | --- | --- | --- | --- | --- | --- |
| Device #1 | 0.6 | 0.4 | 0.4 | 0.5 | 0.1 | 24.7 |
| Device #2 | 0.3 | 0.5 | 0.5 | 0.4 | 0.1 | 26.6 |
| Device # 3 | 0.4 | 0.9 | 1.1 | 0.8 | 0.4 | 45.1 |
| Device # 4 | 1.2 | 1.2 | 1.3 | 1.2 | 0.1 | 4.7 |
| Device # 5 | 0 | 0.2 | 0.8 | 0.3 | 0.4 | 124.9 |
| Device # 6 | 0.6 | 0.3 | 1.2 | 0.7 | 0.5 | 65.5 |
| Device # 7 | 0.8 | 0.5 | 0.5 | 0.6 | 0.2 | 28.9 |
| Device # 8 | 0 | 0 | 0 | 0.0 | 0.0 | 0.0 |
| Device # 9 | 0.3 | 0.4 | 0.4 | 0.4 | 0.1 | 15.7 |
| Device # 10 | 0.2 | 1.4 | 1 | 0.9 | 0.6 | 70.5 |
| Device # 11 | 0.1 | 0.1 | 0.3 | 0.2 | 0.1 | 69.3 |
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| CO Concentration | 5 ppm | | | mean | SD | CV |
| --- | --- | --- | --- | --- | --- | --- |
| Device #1 | 10.1 | 10.3 | 9.9 | 10.1 | 0.2 | 2.0 |
| Device #2 | 9.6 | 10.1 | 10.4 | 10.0 | 0.4 | 4.0 |
| Device # 3 | 14.2 | 11.9 | 11.1 | 12.4 | 1.6 | 13.0 |
| Device # 4 | 10.9 | 11.2 | 10.5 | 10.9 | 0.4 | 3.2 |
| Device # 5 | 11.1 | 11.1 | 11.4 | 11.2 | 0.2 | 1.5 |
| Device # 6 | 9.5 | 10.3 | 10.3 | 10.0 | 0.5 | 4.6 |
| Device # 7 | 11.4 | 9.9 | 10.5 | 10.6 | 0.8 | 7.1 |
| Device # 8 | 10.4 | 10.3 | 9.6 | 10.1 | 0.4 | 4.3 |
| Device # 9 | 11 | 11.9 | 12.9 | 11.9 | 1.0 | 8.0 |
| Device # 10 | 10.6 | 10.8 | 10.7 | 10.7 | 0.1 | 0.9 |
| Device # 11 | 10.3 | 10.4 | 10.5 | 10.4 | 0.1 | 1.0 |
| CO Concentration | 20 ppm | | | mean | SD | CV |
| --- | --- | --- | --- | --- | --- | --- |
| Device #1 | 19.8 | 19.3 | 18.2 | 19.1 | 0.8 | 4.3 |
| Device #2 | 19.2 | 18.9 | 20.2 | 19.4 | 0.7 | 3.5 |
| Device # 3 | 20.9 | 21 | 20.4 | 20.8 | 0.3 | 1.5 |
| Device # 4 | 19.8 | 20.4 | 19.3 | 19.8 | 0.6 | 2.8 |
| Device # 5 | 21.3 | 20.9 | 19.7 | 20.6 | 0.8 | 4.0 |
| Device # 6 | 18.9 | 17.5 | 18.5 | 18.3 | 0.7 | 3.9 |
| Device # 7 | 18.9 | 20.3 | 21.7 | 20.3 | 1.4 | 6.9 |
| Device # 8 | 19.1 | 18.3 | 18.8 | 18.7 | 0.4 | 2.2 |
| Device # 9 | 19.1 | 22.4 | 21.6 | 21.0 | 1.7 | 8.2 |
| Device # 10 | 19.9 | 20.3 | 19.3 | 19.8 | 0.5 | 2.5 |
| Device # 11 | 20.3 | 19.9 | 20.1 | 20.1 | 0.2 | 1.0 |
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| CO Concentration | 50 ppm | | | mean | SD | CV |
| --- | --- | --- | --- | --- | --- | --- |
| Device #1 | 44.7 | 46.3 | 45.7 | 45.6 | 0.8 | 1.8 |
| Device #2 | 48.6 | 48.6 | 48.7 | 48.6 | 0.1 | 0.1 |
| Device # 3 | 47.3 | 49.7 | 49.3 | 48.8 | 1.3 | 2.6 |
| Device # 4 | 46.8 | 47.9 | 46.8 | 47.2 | 0.6 | 1.3 |
| Device # 5 | 51 | 50.9 | 51.6 | 51.2 | 0.4 | 0.7 |
| Device # 6 | 45.7 | 43.6 | 42.7 | 44.0 | 1.5 | 3.5 |
| Device # 7 | 49.8 | 49.9 | 48.4 | 49.4 | 0.8 | 1.7 |
| Device # 8 | 47.4 | 47.7 | 45.4 | 46.8 | 1.3 | 2.7 |
| Device # 9 | 51 | 49.9 | 49.6 | 50.2 | 0.7 | 1.5 |
| Device # 10 | 47.5 | 46.2 | 44.9 | 46.2 | 1.3 | 2.8 |
| Device # 11 | 49.2 | 49.2 | 49.5 | 49.3 | 0.2 | 0.4 |
| CO Concentration | 100 ppm | | | mean | SD | CV |
| --- | --- | --- | --- | --- | --- | --- |
| Device #1 | 92.4 | 93.6 | 93.2 | 93.1 | 0.6 | 0.7 |
| Device #2 | 103.6 | 99.9 | 101.1 | 101.5 | 1.9 | 1.9 |
| Device # 3 | 100.8 | 99.7 | 99.7 | 100.1 | 0.6 | 0.6 |
| Device # 4 | 98.2 | 96.8 | 96.6 | 97.2 | 0.9 | 0.9 |
| Device # 5 | 106.7 | 106.6 | 105.8 | 106.4 | 0.5 | 0.5 |
| Device # 6 | 90.6 | 89.3 | 89.3 | 89.7 | 0.8 | 0.8 |
| Device # 7 | 99.2 | 99.4 | 97.5 | 98.7 | 1.0 | 1.1 |
| Device # 8 | 97.6 | 95 | 96.2 | 96.3 | 1.3 | 1.4 |
| Device # 9 | 109.2 | 108.8 | 104 | 107.3 | 2.9 | 2.7 |
| Device # 10 | 96.1 | 97.3 | 94.1 | 95.8 | 1.6 | 1.7 |
| Device # 11 | 104.4 | 102.1 | 102.1 | 102.9 | 1.3 | 1.3 |
The sponsor also performed a study to demonstrate that the device produces precise and accurate results over the claimed temperature range of $40^{\circ}\mathrm{F} - 104^{\circ}\mathrm{F}$ ( $4^{\circ}\mathrm{C} - 40^{\circ}\mathrm{C}$ ). For each tested temperature of $5^{\circ}\mathrm{C}$ , $10^{\circ}\mathrm{C}$ , $20^{\circ}\mathrm{C}$ , $30^{\circ}\mathrm{C}$ , and $40^{\circ}\mathrm{C}$ , CO concentrations at 5 ppm, 10 ppm, 20 ppm, 50 ppm, and 100 ppm were tested on simulated breath samples in duplicate on each of eleven devices. Results are summarized below:
$5^{\circ}\mathrm{C}$
| CO Concentration | 5 ppm | 10 ppm | 20 ppm | 50 ppm | 100 ppm |
| --- | --- | --- | --- | --- | --- |
| mean | 4.4 | 9.2 | 18.4 | 47.1 | 98.9 |
| SD | 0.5 | 1.1 | 1.5 | 3.2 | 6.5 |
| CV(%) | 11.2 | 12.2 | 8.3 | 6.7 | 6.6 |
| % recovery | 88.0 | 92.0 | 92.0 | 94.2 | 98.9 |
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$10^{\circ}\mathrm{C}$
| CO Concentration | 5 ppm | 10 ppm | 20 ppm | 50 ppm | 100 ppm |
| --- | --- | --- | --- | --- | --- |
| mean | 4.8 | 9.5 | 19.0 | 47.6 | 98.6 |
| SD | 0.5 | 0.8 | 1.3 | 3.0 | 6.7 |
| CV(%) | 10.2 | 8.6 | 6.7 | 6.3 | 6.8 |
| % recovery | 96.0 | 95.0 | 95.0 | 95.2 | 98.6 |
$20^{\circ}\mathrm{C}$
| CO Concentration | 5 ppm | 10 ppm | 20 ppm | 50 ppm | 100 ppm |
| --- | --- | --- | --- | --- | --- |
| mean | 4.7 | 9.2 | 18.9 | 48.1 | 98.8 |
| SD | 0.5 | 0.7 | 1.2 | 2.5 | 6.0 |
| CV(%) | 9.8 | 7.6 | 6.3 | 5.2 | 6.0 |
| % recovery | 94.0 | 92.0 | 94.5 | 96.2 | 98.8 |
$30^{\circ}\mathrm{C}$
| CO Concentration | 5 ppm | 10 ppm | 20 ppm | 50 ppm | 100 ppm |
| --- | --- | --- | --- | --- | --- |
| mean | 4.8 | 9.8 | 19.0 | 49.3 | 101.9 |
| SD | 0.7 | 0.7 | 1.1 | 2.6 | 5.7 |
| CV(%) | 15.2 | 7.2 | 5.8 | 5.3 | 5.6 |
| % recovery | 96.0 | 98.0 | 95.0 | 98.6 | 101.9 |
$40^{\circ}\mathrm{C}$
| CO Concentration | 5 ppm | 10 ppm | 20 ppm | 50 ppm | 100 ppm |
| --- | --- | --- | --- | --- | --- |
| mean | 4.4 | 9.2 | 18.6 | 50.1 | 104.0 |
| SD | 0.5 | 0.5 | 1.1 | 3.1 | 5.6 |
| CV(%) | 11.8 | 5.5 | 6.1 | 6.2 | 5.4 |
| % recovery | 88.0 | 92.0 | 93.0 | 100.2 | 104.0 |
c. Linearity:
The sponsor evaluated linearity through a recovery study. Simulated breath samples at 0 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm, and 100 ppm CO were prepared and analyzed in replicates of 3, on each of 11 devices, for an total of 33 replicates per concentration. A linear regression analysis comparing the measured results with the target concentrations produced the following line equation:
$$
\mathrm{Y} = 0.978\mathrm{x} + 0.487
$$
$$
\mathrm{R}^2 = 0.995
$$
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Average percent recoveries for the non-zero concentrations were determined, as follows:
| Concentration | Average recovery (%) |
| --- | --- |
| 5 | 116.2 |
| 10 | 107.6 |
| 20 | 99.1 |
| 50 | 95.8 |
| 100 | 99.0 |
d. Carryover:
The device contains a lockout feature which prevents the user from performing a breath test if a breath test has been performed or attempted in the previous 5 minutes.
e. Interfering Substances:
The sponsor evaluated the potential for interference from gases other than CO that could be present in exhaled breath by comparing the results from samples containing CO at 20 ppm to samples containing CO at 20 ppm plus one of the potential interferents listed below. The potential interfering gas, the concentration tested, and the mean difference observed are summarized in the table below.
| Potential Interferent | Concentration Tested | Mean Difference Observed |
| --- | --- | --- |
| Hydrogen Sulfide | 15 ppm | 0.2 ppm |
| Sulfur Dioxide | 5 ppm | 0.2 ppm |
| Nitrogen Dioxide | 5 ppm | 0.1 ppm |
| Nitric Oxide | 35 ppm | 1.3 ppm |
| Ethylene | 100 ppm | -1.1 ppm |
| Ethanol | 200 ppm | 0.3 ppm |
2. Other Supportive Instrument Performance Data Not Covered Above:
Lay user labeling comprehension: Seventy lay users were instructed to read the proposed device instructions for use, and to rate how well they understood the instructions, and to rate the ease of use of the device. The lay users were also asked to interpret the device results. Lay users in the study found the device easy to use, and users understood that device results do not indicate that it is safe to smoke.
K. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Parts 801 and 809, as applicable.
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L. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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