The Wrist Blood Pressure Monitor is intended to measure the systolic pressure and diastolic pressure, as well as the pulse rate of adult person via non-invasive oscillometric technique by an inflatable cuff wrapped around the wrist at medical facilities or at home.

Device Description

The Wrist Blood Pressure Monitor is designed as a battery driven automatic non-invasive blood pressure monitor. It can automatically complete the inflation, deflation and measurement, which can measure systolic and diastolic blood pressure as well as the pulse rate of adult person at wrist within its claimed range and accuracy via the oscillometric technique. The result will be displayed in the international unit mmHg or Kpa.

All the models included in this submission follow the the same intended use, same measurement principle, same blood pressure core algorithm and similar product design. All the models can be used with one cuff size 13.5~19.5 cm (5.3-7.7inches).

The main differences are appearance, Dimensions and some specifications which will not affect the safety and effectiveness of the device.

AI/ML Overview

The provided FDA 510(k) clearance letter and associated summary pertain to a Wrist Blood Pressure Monitor, which is a medical device for measuring blood pressure and pulse rate. It is not an AI/Software as a Medical Device (SaMD). Therefore, many of the typical acceptance criteria and study designs associated with AI/SaMD (such as multi-reader multi-case studies, ground truth establishment by experts, training set details, or effect sizes of AI assistance) are not applicable to this device.

The acceptance criteria and study details provided are tailored to the performance of a non-invasive blood pressure measurement system (hardware device), focusing on accuracy, safety, and effectiveness.

Here's a breakdown of the requested information based on the provided document, addressing the device's specific characteristics as a hardware blood pressure monitor:

Acceptance Criteria and Device Performance (Wrist Blood Pressure Monitor)

1. Table of Acceptance Criteria and Reported Device Performance

As per the 510(k) summary, the device's accuracy is a key performance metric. The acceptance criteria are based on the international standard ISO 81060-2 Third edition 2018-11 [Including AMD1:2020].

Performance Metric	Acceptance Criteria (from ISO 81060-2)	Reported Device Performance
Blood Pressure Accuracy	Mean error and standard deviation of differences for systolic and diastolic pressure not over the limits specified in ISO 81060-2.	All data's mean error and standard deviation of differences for systolic, diastolic pressure is not over the limits of ISO 81060-2.
Heart Rate Accuracy	± 5% of reading	± 5% of reading (Same as Predicate, implying met for proposed)

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

Sample Size for Test Set (Clinical Accuracy Study):
- Three groups of clinical accuracy research were conducted. Each group included 100 subjects, for a total of 300 subjects across the 13 models.
- Group 1: 100 subjects (47 Male, 53 Female)
- Group 2: 100 subjects (54 Male, 46 Female)
- Group 3: 100 subjects (44 Male, 56 Female)
- Minimum subjects for each group was 85, as per ISO 81060-2.
Data Provenance: The document does not explicitly state the country of origin for the clinical data. However, the manufacturer is "Shenzhen AOJ Medical Technology Co., Ltd." in Shenzhen, Guangdong, China. It is highly probable the data was collected in China.
Retrospective or Prospective: The clinical accuracy study, designed to meet ISO 81060-2, is typically conducted prospectively to collect new data for device validation. The wording "clinical accuracy research" and "clinical accuracy test report and data analysis followed the requirements" implies a prospective study.

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

This question is not directly applicable in the context of this device because "ground truth" for a blood pressure monitor's accuracy is established against a reference standard, not through expert consensus on interpretations of images or signals (as would be the case for AI/SaMD).
For blood pressure monitors, the "ground truth" or reference measurement is typically taken by trained medical professionals using a standardized reference sphygmomanometer (e.g., mercurial or auscultatory method), as per the ISO 81060-2 standard. The document states "The Same Arm Sequential Method was chosen for all studies," which is a standard procedure comparison method against a reference device. The qualifications of the individuals performing these reference measurements would be trained clinicians (e.g., physicians, nurses).

4. Adjudication Method for the Test Set

This question is not applicable for a blood pressure monitor's accuracy testing. Adjudication methods (like 2+1 or 3+1) are used to resolve discrepancies in human expert interpretations, especially in image-based diagnostics.
For blood pressure accuracy, deviations are quantified statistically between the device reading and the reference measurement, not through an adjudication process among multiple "readers."

5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

No, this was not done. This type of study is relevant for AI/SaMD devices where AI assists human interpretation and is a key component for assessing the AI's clinical utility. The Wrist Blood Pressure Monitor is a standalone hardware device that provides a measurement; it does not involve human "readers" interpreting data or AI assistance.

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

Yes, in essence. The entire clinical accuracy study described in Section 8 ("Clinical data") evaluates the device's performance (which incorporates its internal oscillometric algorithm) in a standalone manner against a reference standard. The "algorithm" here refers to the embedded software that processes the oscillometric signals to derive blood pressure and pulse rate. The study directly assesses how accurately the device (with its integrated algorithm) measures blood pressure readings compared to the reference.
Performance Metrics: The evaluation was based on the "mean error and standard deviation of differences for systolic, diastolic pressure" as per ISO 81060-2.

7. The Type of Ground Truth Used

The ground truth for the clinical accuracy testing was established through concurrent measurements using a standardized reference method (e.g., auscultatory method with a mercurial sphygmomanometer or another validated reference device) on the same arm, sequentially with the test device. This is the standard for blood pressure monitor validation as per ISO 81060-2.
It is not "expert consensus" in the sense of subjective medical interpretation, but rather an objective, standardized measurement performed by trained personnel using a calibrated reference instrument.

8. The Sample Size for the Training Set

This concept is not applicable to this type of medical device clearance. The Wrist Blood Pressure Monitor is a hardware device with an embedded algorithm (oscillometric technique) that is based on established physiological principles. It doesn't use machine learning or deep learning in a way that requires a separate "training set" of patient data for an AI model to learn from, as would be the case for AI/SaMD devices. The device's "training" (development and calibration) would involve engineering principles and laboratory testing, rather than a data-driven machine learning process.

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

As the concept of a "training set" in the context of machine learning is not applicable here (see point 8), the establishment of ground truth for such a set is also not applicable. The device's underlying measurement principle is well-established oscillometric technology. Development and calibration rely on physical models and engineering validation.

Summary

FDA 510(k) Clearance Letter - Wrist Blood Pressure Monitor

Page 1

U.S. Food & Drug Administration
10903 New Hampshire Avenue Doc ID # 04017.07.05
Silver Spring, MD 20993
www.fda.gov

May 2, 2025

Shenzhen AOJ Medical Technology Co., Ltd.
Jack Wang
Deputy Chief
Room 301&4F, Block A, Building A, Jingfa Intelligent Manufacturing Park Xiaweiyuan, Gushu Community, Xixiang Street,
Shenzhen, Guangdong 518126
China

Re: K250161
Trade/Device Name: Wrist Blood Pressure Monitor (Models: AOJ-35A, AOJ-35B, WRS-35B, AOJ35D, AOJ-35E, AOJ-35F, AOJ-35G, WRS-35G, WRS-35H, WRS-35K, WRS35N, WRS-35P, WRS-35S)
Regulation Number: 21 CFR 870.1130
Regulation Name: Noninvasive Blood Pressure Measurement System
Regulatory Class: Class II
Product Code: DXN
Dated: April 3, 2025
Received: April 3, 2025

Dear Jack Wang:

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 (the 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 available 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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K250161 - Jack Wang Page 2

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

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 (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-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 Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/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-devices/device-advice-comprehensive-regulatory-

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K250161 - Jack Wang Page 3

assistance/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,

Stephen C. Browning -S

LCDR Stephen Browning
Assistant Director
Division of Cardiac Electrophysiology,
Diagnostics, and Monitoring Devices
Office of Cardiovascular Devices
Office of Product Evaluation and Quality
Center for Devices and Radiological Health

Enclosure

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FORM FDA 3881 (6/20) Page 1 of 1 PSC Publishing Services (301) 443-6740 EF

DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration

Indications for Use

Form Approved: OMB No. 0910-0120
Expiration Date: 06/30/2023
See PRA Statement below.

510(k) Number (if known)
K250161

Device Name
Wrist Blood Pressure Monitor (Models: AOJ-35A, AOJ-35B, WRS-35B, AOJ-35D, AOJ-35E, AOJ-35F, AOJ-35G, WRS-35G, WRS-35H, WRS-35K, WRS-35N, WRS-35P, WRS-35S)

Indications for Use (Describe)
The Wrist Blood Pressure Monitor is intended to measure the systolic pressure and diastolic pressure, as well as the pulse rate of adult person via non-invasive oscillometric technique by an inflatable cuff wrapped around the wrist at medical facilities or at home.

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)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

This section applies only to requirements of the Paperwork Reduction Act of 1995.
DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

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510(K) Summary

Prepared in accordance with the requirements of 21 CFR Part 807.92

Prepared Date: 2025/01/17

1. Submission sponsor

Name: Shenzhen AOJ Medical Technology Co., Ltd.
Address: Room 301&4F, Block A, Building A, Jingfa Intelligent Manufacturing Park, Xiaweiyuan, Gushu Community, Xixiang Street, Bao'an District, 518126 Shenzhen, PEOPLE'S REPUBLIC OF CHINA
Contact person: Jack Wang
Title: Deputy Chief
TEL: 86 755-27786026

2. Subject Device Information

Trade/Device Name	Wrist Blood Pressure Monitor
Model	models AOJ-35A,AOJ-35B,WRS-35B,AOJ-35D,AOJ-35E,AOJ-35F, AOJ-35G,WRS-35G,WRS-35H,WRS-35K,WRS-35N,WRS-35P, WRS-35S
Common Name	Automatic Blood Pressure Monitor
Regulatory Class	Class II
Product Code	DXN
Submission type	Traditional 510(K)

3. Predicate Device

Manufacturer: Shenzhen AOJ Medical Technology Co., Ltd.
Device name: Wrist Blood Pressure Monitor, models AOJ-35A,AOJ-35B,AOJ-35C,AOJ-35D and AOJ-35E. 510(K) Number: K213503

4. Device Description

The main differences are appearance, Dimensions and some specifications which will not affect the safety and effectiveness of the device.

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5. Intended use & Indication for use

6. Comparison to the Predicate Device

ITEM	Proposed Device	Predicate Device	Comparison Result
	Wrist Blood Pressure Monitor AOJ-35A,AOJ-35B,WRS-35B, AOJ-35D,AOJ-35E,AOJ-35F, AOJ-35G,WRS-35G,WRS-35H, WRS-35K,WRS-35N,WRS-35P, WRS-35S	Wrist Blood Pressure Monitor AOJ-35A,AOJ-35B,AOJ-35C, AOJ-35D,AOJ-35E/ K213503
Manufacturer	Shenzhen AOJ Medical Technology Co., Ltd.	Shenzhen AOJ Medical Technology Co., Ltd.	Same
Intended Use/Indications for Use	The Wrist Blood Pressure Monitor is intended to measure the systolic pressure and diastolic pressure, as well as the pulse rate of adult person via non-invasive oscillometric technique by an inflatable cuff wrapped around the wrist at medical facilities or at home.	The Wrist Blood Pressure Monitor is intended to measure the systolic pressure and diastolic pressure, as well as the pulse rate of adult person via non-invasive oscillometric technique by an inflatable cuff wrapped around the wrist at medical facilities or at home.	Same

Operational Specifications

Parameter	Proposed Device	Predicate Device	Comparison Result
Principle	Oscillometric	Oscillometric	Same
Measurement Item	SYS, DYS, Pulse Rate	SYS, DYS, Pulse Rate	Same
Patient population	Adult	Adult	Same
Measurement site	Wrist	Wrist	Same
Blood pressure measurement range	0-295 mmHg	0-295 mmHg	Same
Accuracy	± 3 mmHg	± 3 mmHg	Same
Heart rate measurement range	40-199 bpm	40-199 bpm	Same
Accuracy	± 5% of reading	± 5% of reading	Same
Cuff size	13.5 - 19.5 cm	13.5 - 19.5 cm	Same
Display	Blood Pressure (Systolic and Diastolic), Pulse rate,Time, Date,BP Indicating Bar, Low Battery Icon,Heart Icon, Memory Record Number	Blood Pressure (Systolic and Diastolic), Pulse rate,Time, Date,BP Indicating Bar, Low Battery Icon,Heart Icon, Memory Record Number	Same
Screen	LCD: AOJ-35A,AOJ-35B,WRS-35B,AOJ-35D,AOJ-35E,AOJ-35F, AOJ-35G,WRS-35G,WRS-35H,WRS-	LCD

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Parameter	Proposed Device	Predicate Device	Comparison Result
	35K,WRS-35N,WRS-35P LED: WRS-35S
Auto shutdown	YES	YES	Same
Operating environment	Temperature: 5°C~40°C Humidity: 15%-90% RH, Atmospheric pressure: 70 kPa -106 kPa	Temperature: 5°C~40°C Humidity: 15%-90% RH, Atmospheric pressure: 70 kPa -106 kPa	Same
Storage environment	Ambient Temperature: -20°C to 55°C Relative Humidity: 10-93% RH, Atmospheric pressure: 70 kPa -106 kPa	Ambient Temperature: -20°C to 55°C Relative Humidity: 10-93% RH, Atmospheric pressure: 70 kPa -106 kPa	Same
Power Source	1)3Vdc (2AAA batteries): AOJ-35A,AOJ-35B,AOJ-35D, WRS-35H,WRS-35K,WRS-35N, WRS-35B,WRS-35S,WRS-35P 2)3Vdc (2AAA batteries) or AC/DC Adapter (DC 5V,1A) AOJ-35E 3)Lithium-ion battery, D.C. 3.7V or AC/DC Adapter (DC 5V,1A) AOJ-35F,AOJ-35G,WRS-35G	3Vdc (2 *AAA batteries)	Different¹
Weight	AOJ-35A: About 126g AOJ-35B: About 126g AOJ-35D: About 128g AOJ-35E: About 127g AOJ-35F: About 141g AOJ-35G: About 126g WRS-35G: About 126g WRS-35H: About 140g WRS-35K: About 138g WRS-35N: About 140g WRS-35B: About 126g WRS-35S: About 125g WRS-35P: About 113g	Approx. 126 g without battery	Different²
Dimensions	AOJ-35A/AOJ-35B/WRS-35B/AOJ-35D: 90mm×66mm×28.5mm AOJ-35E/AOJ-35F: 84mm×70mm×29.3mm AOJ-35G/WRS-35G: 77.6mm×67mm×28.8mm WRS-35H/WRS-35N/WRS-35P: 83.9mm×65.9mm×25.5mm WRS-35K: 84mm×64mm×29mm WRS-35S: 92mm×67.9mm×28.4mm	AOJ-35A/AOJ-35B/AOJ-35D: 90 mm×66 mm×28.5 mm AOJ-35C/AOJ-35E: 79.6 mm×70 mm×26.8 mm
Patient Contacting	Surface-contacting, Less than 24 h	Surface-contacting, Less than 24 h	Same
Biocompatibility evaluation	Cytotoxicity, skin sensitization and	Cytotoxicity, skin sensitization and	Same

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Parameter	Proposed Device	Predicate Device	Comparison Result
	irritation	irritation
Electrical safety	IEC 60601-1 IEC 60601-1-11 ISO 80601-2-30	IEC 60601-1 IEC 60601-1-11 ISO 80601-2-30	Same
EMC	IEC 60601-1-2	IEC 60601-1-2	Same
Biocompatibility	ISO 10993-1 ISO 10993-5 ISO 10993-10	ISO 10993-1 ISO 10993-5 ISO 10993-10	Same
Data transmission	Not available	Not available	Same

Justification for the differences:

1) Different kind of Power Source

Although the device power sources among the predicate devices and subject device are different, they are all complied with IEC 60601-1,IEC 60601-1-2, IEC 60601-1-11 and EC 80601-2-30.So the minor difference do not affect the safety and effectiveness.

2) Different Weight and Dimensions

The subject and the predicate are has slight difference in weight and dimensions due to different outlook.These minor differences do not affect the safety and effectiveness. Moreover, such engineering design has been verified during the international standards, so such minor different ill not raise any safety and effectiveness questions.

7. Non-clinical Data

Biocompatibility testing

Biocompatibility testing performed with the subject device which was provided in previous 510(k)s remains applicable since the device is identical in materials/formulation and processing to the legally marketed device cleared by K213503.

Bench testing

The device has been tested according to the following standards:

IEC 60601-1: Medical Electrical Equipment - Part 1: General Requirements for Basic Safety and essential performance
IEC 60601-1-2: Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral standard: Electromagnetic compatibility - Requirements and tests
IEC 80601-2-30: Medical electrical equipment – Particular requirements for the basic safety and essential performance of automated non-invasive sphygmomanometers.
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
FDA Guidance for Non-Automated Sphygmomanometer.

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8. Clinical data

According to similar clinical characteristics, 13 submitted models were divided into 3 groups for clinical accuracy research.

The clinical accuracy test report and data analysis followed the requirements of the ISO 81060-2 Third edition 2018-11 [Including AMD1:2020] Non-invasive sphygmomanometers - Part 2: Clinical investigation of intermittent automated measurement type [Including: Amendment 1 (2020)].

The Same Arm Sequential Method was chosen for all studies.

Group No.	Test model	Number of Subjects (a minimum of 85 subjects)	Male (at least 30 %)	Female (at least 30 %)	Age range (> 12 years old)
1	AOJ-35A, AOJ-35B, WRS-35B	100	47	53	22 to 80
2	AOJ-35E, AOJ-35D,WRS-35H, WRS-35K, WRS-35N, WRS-35P, WRS-35S	100	54	46	18 to 78
3	AOJ-35F, AOJ-35G, WRS-35G	100	44	56	19 to 80

All data's mean error and standard deviation of differences for systolic, diastolic pressure is not over the limits of ISO 81060-2 Third edition 2018-11 [Including AMD1:2020]. No adverse effect and/or complication is found in this study.

9. Conclusion

It is concluded form the non-clinical and clinical tests that demonstrate that the subject devices are as safe, as effective, and performs as well as the legally marketed predicate device identified above.

K250161

Regulation Number and Section

§ 870.1130 Noninvasive blood pressure measurement system.

(a)
Identification. A noninvasive blood pressure measurement system is a device that provides a signal from which systolic, diastolic, mean, or any combination of the three pressures can be derived through the use of tranducers placed on the surface of the body.(b)
Classification. Class II (performance standards).