The AOJ-25 series Digital Thermometer (except AOJ-25B) are designed as reusable battery-operated electronic device, and intended for the measurement of oral, armpit and rectal temperature for people of all ages at home.
The AOJ-25B is intended to measure temperature rectally only for people of all ages at home as well. The device is reusable.

Device Description

The digital thermometer is designed as hand-held device which can measure human body's temperature orally, axillary (under the arm), or rectally. The results can be displayed on LCD.
The digital thermometers have several functions, such as beep indication, °C and °F unit switchable, low battery detection, memories, three-color backlight, auto automatic power off functions.
The device is a predictive digital thermometer. Users only need 10 seconds for quick reading, and will display the temperature value on the screen.

AI/ML Overview

The provided FDA 510(k) K213485 submission describes the acceptance criteria and the study that proves the Digital Thermometer, Models: AOJ-25A, AOJ-25B, AOJ-25C, AOJ-25D and AOJ-25E meets these criteria.

Here's a breakdown of the requested information:

1. Table of acceptance criteria and the reported device performance

The submission primarily focuses on the clinical accuracy of the thermometer as a key performance criterion, referencing the ISO 80601-2-56 standard.

Acceptance Criteria (from ISO 80601-2-56)	Reported Device Performance
Clinical accuracy of the subject device is at least the same as that of the reference device.	Demonstrated to be accurate within ±0.1°C as claimed in the manual.
No single measurement error exceeding the allowable limit.	Achieved with 99% confidence. Includes a reference device comparison.

Note: The document also mentions other performance aspects like electrical safety, EMC, and biocompatibility, which are met through compliance with relevant IEC and ISO standards. However, specific "acceptance criteria" and "reported performance" are not detailed in a table format for these aspects within the provided text, beyond stating compliance.

2. Sample size used for the test set and the data provenance

Sample Size: A minimum of 90 subjects were used for the clinical accuracy study.
Data Provenance: The document does not explicitly state the country of origin. It indicates a "clinical study" was conducted, referring to it as a "randomization, simple blind homologous control, pairing design of clinical investigation." It is implied to be a prospective study due to the nature of a clinical investigation outlined by the standard.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

The document does not specify the number or qualifications of experts used to establish the ground truth. It states that a "reference device is introduced as required by the standard," implying that the ground truth for temperature measurements during the clinical study was established by this validated reference device, not by human expert interpretation.

4. Adjudication method for the test set

The document mentions a "simple blind homologous control, pairing design of clinical investigation." This suggests a comparative design with a reference device. It does not describe an explicit adjudication method involving multiple human readers for differing interpretations, as the ground truth is based on the objective measurement of temperature by a reference device according to the standard.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done

No, an MRMC comparative effectiveness study was not done. This device is a digital thermometer, not an imaging device requiring human interpretation of clinical images. The study focuses on the accuracy of the temperature measurement itself, not on human readers' interpretation of output.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done

Yes, the clinical accuracy study for the digital thermometer is essentially a standalone performance evaluation of the device in measuring temperature. While the device is used by a human, the performance measured is the accuracy of the device's output against a reference, not its performance in assisting human decision-making or interpretation.

7. The type of ground truth used

The ground truth for the clinical accuracy study was established by a reference device as required by the ISO 80601-2-56 standard. This reference device is used to measure the body temperature against which the subject device's measurements are compared.

8. The sample size for the training set

The document does not provide information about a separate "training set" or its sample size. For medical devices like digital thermometers, the development process typically involves calibration and validation against known standards, which is distinct from the machine learning "training set" concept often associated with AI/ML devices. The "clinical study" described serves as the validation of the final algorithm's accuracy.

9. How the ground truth for the training set was established

As there is no mention of a traditional machine learning training set, the concept of establishing ground truth for it is not applicable here. The device's underlying "algorithm" (firmware) related to temperature measurement would be calibrated and developed based on the physical principles of thermistor resistance and validated through bench testing and the described clinical study against a precise reference thermometer.

Summary

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May 25, 2022

Shenzhen AOJ Medical Technology Co., Ltd. Queena Chen Regulatory Director Room 301&4F, Blk A, Building A, Jingfa IM Park Xiaweiyuan, Gushu Community, Xixiang, Baoan District Shenzhen, Guangdong 518126 China

Re: K213485

Trade/Device Name: Digital Thermometer, Models: AOJ-25B, AOJ-25B, AOJ-25C, AOJ-25D and AOJ-25E Regulation Number: 21 CFR 880.2910 Regulation Name: Clinical Electronic Thermometer Regulatory Class: Class II Product Code: FLL Dated: April 20, 2022 Received: April 25, 2022

Dear Queena Chen:

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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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.

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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 Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

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 https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely.

David Wolloscheck For Payal Patel Assistant Director DHT3C: Division of Drug Delivery and General Hospital Devices, and Human Factors OHT3: Office of GastroRenal, ObGyn, General Hospital and Urology Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K213485

Device Name

Digital Thermometer, Models: AOJ-25A, AOJ-25B, AOJ-25C, AOJ-25D and AOJ-25E

Indications for Use (Describe)

The AOJ-25B is intended to measure temperature rectally only for people of all ages at home as well. The device is reusable.

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

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K213845 - 510(k) Summary

Prepared in accordance with the requirements of 21 CFR Part 807.92

1. Submitter:Contact Person:	Shenzhen AOJ Medical Technology Co., Ltd.Room 301&4F, Block A, Building A, Jingfa Intelligent Manufacturing Park,Xiaweiyuan, Gushu Community, Xixiang Street, Bao'an District, 518126,Shenzhen, ChinaTEL: 86 755-27786026Jack Wang
Prepare date:	May 24, 2022
2. Device nameand classification:	Trade Name: Digital ThermometerModels: AOJ-25A, AOJ-25B, AOJ-25C, AOJ-25D and AOJ-25ECommon Name: Clinical Electronic ThermometerClassification Number/Name:21 CFR 880.2910Clinical Electronic ThermometersProduct code: FLL
3. Reason forSubmission:	Regulatory Class: Class IINew Application. No prior submission for this device before.
3. Class III devicestatement	Not applicable, the subject device is a Class II device.
4. PredicateDevice(s):5. DeviceDescription:	Joytech Healthcare Co., Ltd, Digital Thermometer, Model DMT-4726, K183393The digital thermometer is designed as hand-held device which can measure humanbody's temperature orally, axillary (under the arm), or rectally. The results can bedisplayed on LCD.The digital thermometers have several functions, such as beep indication, °C and °Funit switchable, low battery detection, memories, three-color backlight, autoautomatic power off functions.The device is a predictive digital thermometer. Users only need 10 seconds forquick reading, and will display the temperature value on the screen.
6. Indications forUse:	The AOJ-25 series Digital Thermometer (except AOJ-25B) are designed as reusablebattery-operated electronic device, and intended for the measurement of oral, armpitand rectal temperature for people of all ages at home.The AOJ-25B is intended to measure temperature rectally only for people of all ages athome as well. The device is reusable.

7. Substantial Equivalence Discussion

Comparison to the predicate devices, the subject device has same intended use, similar product design, same performance effectiveness, performance safety as the predicate device.

Please refer to following table to find differences between the subject device and predicate device. All the differences do not affect the basic design principle, usage, effectiveness and safety of the subject device. And no question is raised regarding to effectiveness and safety.

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ITEM	Proposed DeviceAOJ-25A, AOJ-25B, AOJ-25C,AOJ-25D, AOJ-25E	Predicate DeviceDMT-4726/K183393	ComparisonResult
Manufacturer	Shenzhen AOJ Medical Technology Co.,Ltd.	Joytech Healthcare Co., Ltd
IntendedUse/Indications forUse	The AOJ-25 series DigitalThermometer(except AOJ-25B) aredesigned as reusable battery-operatedelectronic device, and intended for themeasurement of oral, armpit and rectaltemperature for people of all ages at home.The AOJ-25B is intended to measuretemperature rectally only for people of allages at home as well. The device is reusable	The Digital Thermometers DMTseries(Except DMT-455) are intendedto measure the human bodytemperature in regular mode orally,rectally or under the arm. And thedevices are reusable for clinical orhome use on people of all ages,including children under 8 with adultsupervision.	Different 1
Operational Specifications
Operational principle	A change of thennistor resistance, causedby changes of temperature. The resistanceis measured by MCU, so changes oftemperature will correspond to changes ofresistance	A change of thermistor resistance,caused by changes of temperature.The resistance is measured by MCU,so changes of temperature willcorrespond to changes of resistance	Same
Sensor	Thermistor	Thermistor	Same
Components	Sensor, buzz film, housing, stainless steelcap, LCD display, measurement controlmodule.	Sensor, buzz film, housing, stainlesssteel cap, LCD display, measurementcontrol module.	Same
Signal processingand display	Internal firmware and localLCD display	Internal firmware and localLCD display	Same
Predictive mode	YES	Optional	Different 2
Measurement site	orally, rectally or under the arm(except AOJ-25B, rectal only)	orally, rectally or under the arm	Same
Measurement range	32.0°C- 42.9°C	32.0°C- 43.9°C	Different 2
Accuracy	0.1 °C (35.5°C-42°C)0.2 °C(< 35.5°C or > 42.0°C)	±0.1 °C (35.5°C-42.0°C)±0.2 °C(< 35.5°C or > 42.0°C)
Memory data	10 memories	10 memories	Same
Automatic shutdown	YES	YES	Same
Temperature unit andconversion	Dual temperature units "°C" and "°F"optional, and the two units can convert bythe conversion key automatically	Dual temperature units "°C" and "°F"optional, and the two units canconvert by the conversion keyautomatically	Same
Operatingenvironment	Temperature: 10°C- 40°CHumidity: 30%-85% RH, non-condensingAtmospheric pressure: 70-106 kPa	Temperature: 5°C-40°CHumidity: 15%-95% RH,non-condensingAtmospheric pressure: 70- 106 kPa	Different 3
Storage environment	Ambient Temperature:- 20 °c to 55°CRelative Humidity: 10-93% RH,non-condensingAtmospheric pressure: 70kPa to 106kPa	Ambient Temperature:- 20 °c to 55°CRelative Humidity: 0-95% RH,non-condensingAtmospheric pressure: 50kPa to106kPa
Battery type	One 3.0V CR2032 battery	One 3.0V CR2032 battery	Same
Applied Standards
Electrical safety	IEC 60601-1IEC 60601-1-11	IEC 60601-1IEC 60601-1-11	Same

					Table 1 Comparison between predicate DMT-4726 and the subject device AOJ-25 series
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EMC	IEC 60601-1-2	IEC 60601-1-2	Same
Biocompatibility	ISO 10993-1ISO 10993-5ISO 10993-10	ISO 10993-1ISO 10993-5ISO 10993-10	Same
Physical Specifications
Weight	AOJ-25A/AOJ-25C/AOJ-25E:Approx. 23 grams without batteryAOJ-25B: Approx. 26 grams includingbattery	Approx. 40 grams including battery	Different 4
Dimensions(Lx Wx H)	AOJ-25A/AOJ-25C/AOJ-25E:142mmx30mmx 14mmAOJ-25B: 93mm x 34.5mm x 18mm	106 mm x 32 mm x 25 mm
Display screen	LCD	LCD	Same
Biological Specifications
Patient ContactingMaterials	ABS,TPU,Stainless steel	ABS,TPE,Stainless steel	Different 5
Patient Contacting	Surface-contacting,Less than 24 h	Surface-contacting,Less than 24 h	Same
Biocompatibilityevaluation	Cytotoxicity, skin sensitization andirritation	Cytotoxicity, skin sensitization andirritation	Same

Justification for the differences:

1. Different Indications for Use
  As indicated in the comparison table, the application scenario of the predicate device can be used both in hospital and home, while the subject device can be used at home. The absence of application in clinical use reduces the operation risks, no raise of new questions on the safety and effectiveness.
1. Different measurement range
  The subject device measurement range has been evaluated per the internal standards ISO 80601-2-56, the results tell the accuracy can be matched as claimed, no extra risk will be introduced due to the minor difference.
1. Different Operation, storage, and transportation Environments
  Minor difference to operation and storage and transportation environments for the subject device, but the system has been proved to be safe and effective since the safety testing was conducted under the suggested environment; Moreover, environment testing data shows the device can work as declared under the suggested conditions. So those changes will not cause any safety and effectiveness problem.
1. Different Physical Specifications
  The subject and the predicate are of different size but proximity. Moreover, such engineering design has been verified during the international standards, so such minor different ill not raise any safety and effectiveness questions.
1. Different Patient Contacting Materials
  Minor different material used for the housing, but both comply with the same standards, and evaluated to be safe after the biocompatibility testing as defined in Annex I of ISO 10993-1. Therefore, this material difference will not cause any safety and effectiveness problem.

As seen in the comparison tables, the subject and predicate devices have almost the same design features and performance specifications. The differences between the subject and predicate devices do not raise different

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questions of safety oreffectiveness. Moreover, as demonstrated in the bench testing, the different technological characteristics do not affect the safety and effectiveness of the subject device.

8. Performance Testing:

Performance data includes "Non-Clinical Data", brief description of which are shown as below.

Non-Clinical Data:

The following performance data were provided in support of the substantial equivalence determination.

Biocompatibility testing

The biocompatibility evaluation for the digital thermometer were conducted in accordance with the International Standard ISO 10993-1 "Biological Evaluation of Medical Devices - Part 1: Evaluation and Testing Within a Risk Management Process," as recognized by FDA. The contact classification is considered mucosalmembrane contacting for a duration of less than 24 hours. The battery of testing included the following tests:

Cytotoxicity
Skin Sensitization
Skin Irritation

Electrical safety and electromagnetic compatibility (EMC)

Electrical safety andEMC testing were conducted on the digital thermometer device. The device complies with the IEC 60601-1 Medical electrical equipment Part 1: General requirements for basic safety and essential performance for safety, IEC 60601-1-11 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, and the IEC 60601-1-2 Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral Standard: Electromagnetic disturbances - Requirements and tests standard for EMC.

Bench Testing

Bench testing was conducted on the digital thermometer device, consisting of all the accessories in the system. The system complies with the ISO 80601-2-56 Medical electrical equipment - Part 2-56: Particular requirements for basic safety and essential performance of clinical thermometers for body temperature measurement for performance effectiveness.

Software Verification and Validation Testing

Software verification and validation testing were conducted and documentation was provided as recommended by FDA's Guidance for Industry and FDA Staff, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices." The software for this device was considered as a "moderate" level of concern.

Clinical data:

The CLINICAL ACCURACY in each adjusted mode was validated per the requirements defined in clause 201.102 of international standard ISO 80601-2-56. This clinical study is a randomization, simple blind homologous control, pairing design of clinical investigation, consists of a minimum of 90 subjects as required, and divided into four age groups as defined in Table 201.102 of the standard shown as below.

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Age group	Age[11]
A1	0 up to 3 months
A2	3 months up to 1 year
B	older than 1 year and younger than 5 years
C	older than 5 years

Table 201.102 - Subject age groups

No single measurement error exceeding the allowable limit, provides a 99% confidence. A reference device is introduced as required by the standard, and the acceptance criteria is that clinical accuracy of the subject device is at least the same as that of the reference, and the accuracy is ±0.1℃ as claimed in the manual.

Summary

Based on the non-clinical performance data as documented in the device development, the subject devices were found to have a similar safety and effectiveness profile as the predicate device.

9. Conclusion:

The differences between the predicate and the subject device do not raise any new or different questions of safety and effectiveness. Verification and validation testing was conducted on the subject device and all testing passed pre-specified criteria. This premarket notification submission demonstrates that the AOJ-25 series Digital Thermometer is substantially equivalent to the predicate device.

Regulation Number and Section

§ 880.2910 Clinical electronic thermometer.

(a)
Identification. A clinical electronic thermometer is a device used to measure the body temperature of a patient by means of a transducer coupled with an electronic signal amplification, conditioning, and display unit. The transducer may be in a detachable probe with or without a disposable cover.(b)
Classification. Class II (performance standards). The device is exempt from the premarket notification procedures in part 807, subpart E of this chapter, subject to the limitations in § 880.9 and the following conditions for exemption:(1) Device is not a clinical thermometer with telethermographic functions;
(2) Device is not a clinical thermometer with continuous temperature measurement functions; and
(3) Appropriate analysis and testing (such as that outlined in the currently FDA-recognized editions, as appropriate, of ISO 80601-2-56, “Medical electrical equipment—Part 2-56: Particular requirements for basic safety and essential performance of clinical thermometers for body temperature measurement,” or ASTM E1965, “Standard Specification for Infrared Thermometers for Intermittent Determination of Patient Temperature,” or ASTM E1112, “Standard Specification for Electronic Thermometer for Intermittent Determination of Patient Temperature,” or ASTM E1104, “Standard Specification for Clinical Thermometer Probe Covers and Sheaths”) must validate specifications and performance of the device.