← Product Code [QZA](/submissions/HO/subpart-c%E2%80%94general-hospital-and-personal-use-monitoring-devices/QZA) · DEN230050 # Body Temperature Software (BTS) (DEN230050) _Fitbit, LLC · QZA · Dec 15, 2023 · General Hospital · DENG_ **Canonical URL:** https://fda.innolitics.com/submissions/HO/subpart-c%E2%80%94general-hospital-and-personal-use-monitoring-devices/QZA/DEN230050 ## Device Facts - **Applicant:** Fitbit, LLC - **Product Code:** [QZA](/submissions/HO/subpart-c%E2%80%94general-hospital-and-personal-use-monitoring-devices/QZA.md) - **Decision Date:** Dec 15, 2023 - **Decision:** DENG - **Submission Type:** Direct - **Regulation:** 21 CFR 880.2915 - **Device Class:** Class 2 - **Review Panel:** General Hospital - **Attributes:** Software as a Medical Device, Pediatric ## Indications for Use The Body Temperature Software (BTS) App is a software-only mobile medical application intended for over-the-counter (OTC) use with compatible mobile computing platforms that includes a general purpose infrared sensor for the intermittent determination of human body temperature on people of all ages. ## Device Story BTS is a mobile medical application; utilizes input from a general-purpose infrared sensor on compatible mobile computing platforms; performs intermittent determination of human body temperature; intended for OTC use by patients of all ages; software processes raw sensor data to calculate temperature; output displayed to user for health monitoring; assists in clinical decision-making regarding potential fever or temperature abnormalities; benefits patient by providing accessible, non-invasive temperature tracking. ## Clinical Evidence Prospective, single-arm, multi-center observational study (n=144) compared BTS to a legally marketed comparator. Subjects included newborns, infants, children, adolescents, and adults. Primary endpoint: clinical bias and Limits of Agreement (LOA). Overall clinical bias was +0.04°C. Upper LOA: 1.02°C (95% CI: 0.85°C, 1.18°C); Lower LOA: -0.94°C (95% CI: -1.09°C, -0.78°C). Accuracy confirmed within 36°C-40°C range. Usability study (n=31) confirmed safe/effective use by lay users and caregivers. ## Technological Characteristics Software-only mobile medical application; utilizes general-purpose infrared sensor input; requires compatible mobile computing platforms; includes algorithm for temperature calculation; subject to software verification, validation, and hazard analysis; performance specifications and signal quality detection required. ## Regulatory Identification Body temperature sensing software is a software device used for the determination of human body temperature by means of analyzing input sensor data. The Body Temperature Software (BTS) App is a software-only mobile medical application intended for over-the-counter (OTC) use with compatible mobile computing platforms that includes a general purpose infrared sensor for the intermittent determination of human body temperature on people of all ages. ## Special Controls In combination with the general controls of the FD&C Act. the body temperature sensing software is subject to the following special controls: ## Submission Summary (Full Text) > This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com. > > Innolitics is a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices, including [a De Novo](https://innolitics.com/services/regulatory/), [a 510(k)](https://innolitics.com/services/510ks/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/). {0}------------------------------------------------ # DE NOVO CLASSIFICATION REQUEST FOR BODY TEMPERATURE SOFTWARE (BTS) #### REGULATORY INFORMATION FDA identifies this generic type of device as: Body temperature sensing software. Body temperature sensing software is a software device used for the determination of human body temperature by means of analyzing input sensor data. NEW REGULATION NUMBER: 21 CFR 880.2915 CLASSIFICATION: Class II PRODUCT CODE: QZA #### BACKGROUND DEVICE NAME: Body Temperature Software (BTS) SUBMISSION NUMBER: DEN230050 DATE DE NOVO RECEIVED: July 17, 2023 #### CONTACT: Fitbit LLC 199 Fremont Street San Francisco, CA 94105 #### INDICATIONS FOR USE The Body Temperature Software (BTS) App is a software-only mobile medical application intended for over-the-counter (OTC) use with compatible mobile computing platforms that includes a general purpose infrared sensor for the intermittent determination of human body temperature on people of all ages. #### LIMITATIONS The feature has not been tested for and is not intended to be used to measure the body temperature of a premature baby (defined as less than or equal to 37 calendar weeks gestational age at birth). Use of the BTS App is not intended to diagnose or monitor a serious medical condition or disease and is not a substitute for a consultation with a healthcare professional. Don't interpret or take clinical action based on the device output without consulting a qualified healthcare professional. {1}------------------------------------------------ This device CANNOT detect illnesses. This device DOES NOT replace the advice of your healthcare provider. This device should be operated by persons over 18 years of age. DO NOT use this device to measure body temperature when exposed to the following conditions: - . Excessive motion (e.g., operating machinery, walking), and/or - Direct sun or near radiant heat sources (e.g., heaters). . DO NOT use this device to measure body temperature when the smartphone is visibly damaged, or has sensors or ports obstructed. Reference manufacturer instructions for maintenance. DO NOT use this device to measure body temperature when the external environmental temperature is outside of 15°C - 35°C (59°F - 95°F). DO NOT use this device to measure body temperature if you suspect hypothermia. PLEASE REFER TO THE LABELING FOR A MORE COMPLETE LIST OF WARNINGS, PRECAUTIONS AND CONTRAINDICATIONS. #### DEVICE DESCRIPTION The Body Temperature Software (BTS) is a mobile medical application available to its intended users via their mobile device. The Body Temperature Software (BTS) collects and analyzes temperature data obtained via the infrared sensor built into the smartphone to approximate the user's rectal temperature which is then displayed on the application's user interface. The Body Temperature Software (BTS) is a pre-installed application on the Pixel 8 Pro with Android 14 operating system release or higher. | Software | Body Temperature Software (BTS) | |-----------------------------|-------------------------------------------------------------| | Hardware | Pixel 8 Pro (Android 14 operating system release or higher) | | Intended Users | All users over the age of 18 | | Intended Patient Population | General population excluding premature/preterm infants | Users must opt-in and go through an onboarding process prior to use of the Body Temperature Software (BTS) application. The Body Temperature Software (BTS) onboarding process consists of a pop-up screen requiring user acknowledgement of the intended use, patient population, and user population followed by a video walkthrough demonstrating the kev steps necessary to obtain a temperature measurement. These steps include (1) identifying the sensor on the back of the phone, (2) removal of accessories that cover the forehead and temple, (3) place the sensor as close to the center of the forehead without touching, and (4) conducting the measurement sweep from the center of the forehead to the temple within four (4) seconds. The hardware platform provides audible, visual, and tactile feedback in addition to voice assist during these steps. The {2}------------------------------------------------ audible, visual, and tactile feedback are intended to communicate the process steps (e.g., appropriate distance to forehead, counting of seconds of the forehead sweep) related to obtaining a temperature measurement during the forehead sweep. The voice assist is intended to provide audio guidance supplementary to the existing feedback. After the four (4) second forehead sweep, the temperature data is then used as an input into the Body Temperature Software (BTS) algorithm to convert the measured skin temperature data into a body temperature value representative of an approximation of rectal temperature results are able to be stored in the mobile application for seven (7) days. This information includes the time and date of the measurement, age range associated with the temperature guidance if enabled, and the temperature result. Within the Body Temperature Software (BTS) mobile application, a user may enable the Temperature Guide that informs users whether their temperature measurement indicates a normal, elevated, or high temperature based on medical literature. The results of this functionality are based on the age range chosen prior to taking a measurement. The age ranges include 0-3 months. 3-36 months, 3+ years. The application performs a series of checks prior to launching the application, during the measurement sweep, and during the processing of the signal to ensure that the temperature data collected is valid for processing. Using this valid collected data, the algorithm processes the sensor data collected during the sweep and displays a measurement to the user that approximates rectal temperature. To enable the mobile application to obtain a temperature measurement, the systems check, proximity detection, and infrared sensor checks must pass. If the signal quality checks are deemed acceptable, following additional proximity and internal infrared sensor ambient temperature checks, additional signal quality checks are performed upon signal ingestion to the algorithm and again at subsequent points throughout the algorithm analysis to verify that the signal received by the sensor is accurate and reliable. If these checks fail, error messages are intended to inform the user when the collected signal is not of sufficient quality. The potential error messages include 'Sensor out of range', 'Unable to start measurement', 'Measurement failed', 'Temperature sensor is too warm/too cool', and 'Temperature sensor unavailable'. In addition to the signal quality checks implemented within the Body Temperature Software (BTS) process flow to obtain an accurate temperature measurement, pre-specified requirements for the hardware platform (e.g., operating system, processor speed, memory, etc.), sensor (e.g., sensor type, sensitivity, accuracy, etc.), and signal quality (e.g., maximum forehead temperature, infrared sensor internal temperature, estimated body temperature, sensor to sensor window difference, proximity, system check) must be met. # SUMMARY OF NONCLINICAL/BENCH STUDIES #### SOFTWARE The Body Temperature Software has a Moderate Level of Concern (LOC). Appropriate documentation was provided to support the validation of the software for a Moderate LOC in {3}------------------------------------------------ accordance with FDA's 2005 guidance titled, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices." # PERFORMANCE TESTING - BENCH The Body Temperature Software (BTS) was subjected to a series of bench tests to assess its functional performance under nominal conditions and conditions exposing the device to factors that may impact signal quality. These tests were performed in conformance with ISO 80601-2-56:2017 Medical electrical equipment - Part2-56: Particular requirements for basic safety and essential performance of clinical thermometers for body temperature measurement using the final version of the device or a version of the device that was sufficiently representative of the final version of the device. The bench testing summarized in the table below was performed to demonstrate acceptable performance of the device for its intended use. | Test | Description | |----------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | Range Check Flag | Demonstrate that the range enable flag correctly captures
distance and gates forehead temperature measurement
signals when within a specified range from the user's
forehead. | | Infrared Sensor Internal
(Ambient) Temperature (TA)
Check Flag | Demonstrate that internal temperature of the infrared sensor
can sufficiently and correctly measure the internal
temperature and sensor window temperature and gates
forehead temperature within a specified range. | | Robustness to External
Aggressors | Demonstrate that variations in the inputs due to a variety of
common and/or expected behavioral and physiological
conditions do not affect the performance of the algorithm
significantly. These conditions include motion artifacts,
environment, and wear condition/position of the device. | | Fitzpatrick/Monk Level
Performance | Demonstrate that the infrared sensor signal quality does not
vary significantly across various skin tones, and skin tone
emissivity does not impact algorithm performance. | | Hardware Equivalency | Demonstrate that variations of the hardware and software
components found on compatible Pixel mobile devices have
no significant effect on the signal quality of the data
provided as inputs for the algorithm. | | Skin Temperature Range
Check | Demonstrate that the filtered maximum forehead
temperature must be in the range of 30°C to 40°C, which is
inclusive of the human body temperature range. | | Body Temperature Check | Demonstrate that the calculated maximum temperature must
be in the range of 34.5°C to 43°C which is inclusive of the
human body core temperature range. | Performance/Input Signal Testing (Bench) Summary {4}------------------------------------------------ | Test | Description | |-----------------------------------------------------|---------------------------------------------------------------------------------------| | Window & Sensor
Temperature Differences
Check | Demonstrate that the sensor-to-sensor window temperature
difference is $\leq$ 2°C. | # SUMMARY OF CLINICAL INFORMATION # Clinical Study The Sponsor provided data from a clinical study as well as literature to support the clinical accuracy of the Body Temperature Software (BTS). This study used data collected from a subset of participants enrolled in a prospective. single-arm, multi-center observational study conducted to demonstrate the Body Temperature Software (BTS) produces temperature measurements within the specified clinical accuracy criteria when compared to a legally marketed comparator device in conformance with ISO 80601-2-56:2017 Medical electrical equipment - Part2-56: Particular requirements for basic safety and essential performance of clinical thermometers for body temperature measurement. A total of 145 racially and ethnically diverse subjects were enrolled in the clinical study, including 37 newborns and infants (0 to < 2 years), 36 children (2 to < 12 years), 37 adolescents and transitional adolescents (12 to < 18 years), and 35 adults (≥ 22 years). A total of 144 subjects completed the study. The statistical analyses used the data collected in its entirety as well as age and race subgroup analyses. Each subject's body temperature measurements were obtained using the Body Temperature Software (BTS) and comparator device. A total of six (6) temperature measurements were obtained on each participant, three (3) with the Body Temperature Software (BTS) and three (3) with the comparator device. The primary endpoint was to determine the clinical bias, including the Limits of Agreement (LOA), between the Body Temperature Software (BTS) and comparator device. Overall. the clinical bias was within the established acceptance criteria and supports use of the device in the intended patient population. The clinical bias for the entire patient population was +0.04°C when calculated using the mean of the three (3) comparator device readings. The associated upper and lower LOAs were -0.94°C (-1.09°C. -0.78°C 95% CI) and 1.02°C (0.85°C. 1.18°C 95% CI), respectively. The accuracy of the subject device was determined to be within the stated temperature range of 36℃ and 40℃. # Human Factors and Usability Study The Sponsor provided a Human Factors and Usability study which included a total of 31 participants from the following two user groups for the Body Temperature Software (BTS): - . 16 lay people at least 18 years of age who use Android smartphones. - 15 lay caregivers at least 18 years of age who use an Android smartphone and provide . care for another individual. {5}------------------------------------------------ All participants used the Body Temperature Software (BTS) mobile application which included videos and instructions embedded in the application's software interface. Apart from the initial onboarding video that is played prior to taking a first temperature reading, no additional training was provided to the study participants. Overall, usability testing demonstrated that the Body Temperature Software (BTS) is safe and effective for the intended users, uses, and use environments. # LABELING The labeling for the device satisfies the requirements of 21 CFR 801.109. The labeling consists of adequate Instructions for Use, an onboarding sequence, and pop-up messages in the user interface. The Instructions for Use include the indications for use, a description of the device. cautions, warnings and limitations, information regarding the temperature guidance functionality, operating instructions, troubleshooting, overview of the clinical study, and device performance specifications. Please see the Limitations section above for important warnings and precautions presented in the device labeling. # RISKS TO HEALTH The table below identifies the risks to health that may be associated with use of body temperature sensing software and the measures necessary to mitigate these risks. | Risk to Health | Mitigation Measures | |-------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------| | Inaccurate device output leading
to patient receiving incomplete
or delayed treatment/diagnosis | Clinical performance testing
Non-clinical performance testing
Software verification, validation, and hazard analysis
Labeling | | Poor signal quality resulting in
failure to detect elevated body
temperature | Non-clinical performance testing
Software verification, validation, and hazard analysis
Labeling | Identified Risks to Health and Mitigation Measures # SPECIAL CONTROLS In combination with the general controls of the FD&C Act. the body temperature sensing software is subject to the following special controls: - For devices where the output temperature is calculated by adjusting the signal from the (1) input sensor, clinical performance testing must demonstrate the accuracy of the device under anticipated conditions of use. - (2) Non-clinical performance testing must demonstrate the ability of the device to detect adequate signal quality under anticipated conditions of use. Testing must evaluate: - (i) The laboratory accuracy of the device across the intended output range under the intended operating conditions: and - (ii) The impact of confounding factors on device accuracy. {6}------------------------------------------------ - (3) Software verification, validation, and hazard analysis must be performed. Documentation must include a characterization of the technical specifications of the software, including the application algorithm and its inputs and outputs. - (4) Labeling must include: - (i) Compatible hardware platform(s) and operating system requirements: - Situations in which the device may not operate at an expected performance level; (ii) - A summary of the clinical performance testing conducted with the device, (iii) including a description of the reference body site: - Established device performance specifications: and (iv) - Information on interpretation of results. (v) # BENEFIT/RISK DETERMINATION The Body Temperature Software (BTS) is intended to approximate rectal temperature. The device demonstrated a laboratory accuracy of ±0.3℃ and met clinical accuracy requirements of ISO 80601-2-56 for the intended patient population. The device is not intended to diagnose users or patients with a condition or illness, but it provides an accessible tool to monitor body temperature. The probable benefits of the Body Temperature Software (BTS) are that the device is easily accessible, convenient to use, is comparable to other legally marketed non-contact infrared thermometers and demonstrates favorable clinical performance in regard to clinical bias. The device is available on a mobile platform that is easy to navigate, clean, and disinfect as needed. The temperature is provided after a quick four (4) second temperature sweep across the forehead and these results are able to be saved up to seven (7) days for personal or clinical reasons. The risks for the Body Temperature Software (BTS) include inaccurate device outputs leading to patients receiving incomplete or delayed treatment/diagnosis and poor signal quality resulting in failure to detect elevated body temperature. Non-clinical testing, under the conditions of use and conditions that may impact signal quality, is required to: 1) ensure that the device is provided with sufficient temperature data from the infrared sensor, and 2) characterize the likelihood of inaccurate outputs. Labeling is also required to help the user interpret the results they receive. Here, the labeling specifically states the conditions for use and that the device is not intended to replace a healthcare professional's opinion. The Body Temperature Software (BTS) does include some additional considerations that may impact signal quality that are not present in currently marketed non-contact infrared thermometers (i.e., confounding factors). Some of these confounding factors have been assessed through performance testing and demonstrated the accuracy specification is not impacted. For those not tested and those found to impact accuracy through bench testing, the labeling and user interface of the device (available through the application) warns users of these environments and factors. In such cases, the Body Temperature Software (BTS) would return an error that the measurement failed, or a condition has not been met such that a temperature reading could not be provided. {7}------------------------------------------------ Overall, the benefit of an easily accessible thermometer outweighs the risks of inaccurate results and failure to detect elevated body temperature as a result of poor signal quality given the mitigations employed including the special controls in combination with the general controls. There is a reasonable assurance of safety and effectiveness for the device when used as intended. A majority of the risks associated with the BTS app are consistent with risks that exist for currently marketed non-contact infrared thermometers. #### Patient Perspectives This submission did not include specific information on patient perspectives for this device. #### Benefit/Risk Conclusion In conclusion, given the available information above, the data support that for the Body Temperature Software (BTS), the probable benefits outweigh the probable risks. The device provides benefits, and the risks can be mitigated by the use of general controls and the identified special controls. #### CONCLUSION The De Novo request for the Body Temperature Software (BTS) is granted and the device is classified under the following: Product Code: QZA Device Type: Body temperature sensing software Class: II Regulation: 21 CFR 880.2915 --- **Source:** [https://fda.innolitics.com/submissions/HO/subpart-c%E2%80%94general-hospital-and-personal-use-monitoring-devices/QZA/DEN230050](https://fda.innolitics.com/submissions/HO/subpart-c%E2%80%94general-hospital-and-personal-use-monitoring-devices/QZA/DEN230050) **Published by [Innolitics](https://innolitics.com)** — a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices. 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