K Number
K031582
Date Cleared
2003-08-01

(72 days)

Product Code
Regulation Number
870.2770
Reference & Predicate Devices
Predicate For
N/A
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

Combination unit for measuring systolic and diastolic blood pressures and pulse rates in adult patients with arm circumference between 4.9" to 8" inches as well as body composition, i.e. estimation of body fat, a noninvasive bioimpedance analyzer for use in estimating the human's body fat volume (mass) and percentage by weight. Age range 10-80 years normal subjects, 18-80 years for athletic subjects.

Device Description

The Model WT-20 Wrist Blood Pressure Monitor & Fat Meter combines the familiar wrist blood pressure monitor found over the counter in drug stores with a body composition/body fat meter.

AI/ML Overview

Here's an analysis of the provided text to extract the requested information about acceptance criteria and the study proving the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance:

The document describes the device, the Nissei WT-20 Wrist Blood Pressure Monitor & Fat Meter, as substantially equivalent to predicate devices. This implies that the 'acceptance criteria' for the Nissei WT-20 are that its performance is comparable to or meets the specifications of the predicate devices. The study provided focuses on this comparison rather than defining explicit numerical acceptance criteria for a new, unique performance claim.

CharacteristicPredicate Device (OMRON Body Fat Analyzer HBF-306)Nissei WT-20 (Reported Performance)Acceptance Criteria (Implied)
Operating PrincipleBioelectrical Impedance Analysis (BIA)SAME (Also measures blood pressure)Must be BIA for fat measurement
Display (Body Fat %)4.0 to 50.0%5.0 to 50.0%Functionally similar range (within acceptable variance)
Display (BMI)7.0 to 90.05 to 100Functionally similar range (within acceptable variance)
BMI Classification4 levels4 levelsSame number of classification levels
Measurement Time7 Seconds5 to 10 secondsSimilar measurement time frame
Height Range3'4" to 6'6" (101cm. to 198cm.)36 to 79 inches (appears to be a slightly wider range: 3 ft to 6ft 7in)Covers a similar range of heights
Weight Range23lbs. to 440 1/2 lbs (10kg.to220kg.)22 to 440 pounds (appears slightly different at the lower end)Covers a similar range of weights
Age Range (Normal)10 to 80 years old10 to 80 (age)Covers the same age range
Age Range (Athlete)18 to 60 years oldIndicated 18-80 years for athletic subjects in Indications for Use. The table only says "10 to 80 (age)".Covers the same or broader age range
GenderMale / FemaleMale or female (sex)Supports both genders
Power Supply2 AAA batteries (R03)SAME (Alkaline recommended)Uses 2 AAA batteries
Memory9 personal profile memories4 sets of weight, height, age, sex and 10 measurement results of blood pressure and body fatProvides memory for user profiles and historical measurements
Indications for UseNot explicitly stated for HBF-306, but implied for body fat estimation.Measuring systolic and diastolic blood pressures and pulse rates, and body composition (body fat volume and percentage).Performance for body fat: comparable to predicate. Blood pressure: comparable to WS-500

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

The document mentions "clinical testing data" but does not explicitly state the sample size (number of participants) used for the test set for the body fat measurement or blood pressure features. The provenance of the data (country of origin, retrospective or prospective) is also not specified.

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

The document does not provide information on the number or qualifications of experts used to establish ground truth for the test set. Given the nature of a 510(k) submission for substantial equivalence, the "ground truth" for the body fat measurement would likely be established through comparison to a well-accepted clinical standard (e.g., DEXA or underwater weighing), and for blood pressure, comparison to a validated manual sphygmomanometer. However, the details of these comparisons are not in the provided text.

4. Adjudication Method for the Test Set:

The document does not describe any adjudication method for the test set.

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

No MRMC comparative effectiveness study is mentioned. The device is a direct measurement tool, not an interpretive one typically evaluated by MRMC studies (which often involve human readers interpreting images, for example).

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

The provided text details a comparison of the device's technical specifications and intended use against predicate devices. The "Summary of Safety and Effectiveness" states that "The results of bench and user testing indicate that the new device is as safe and effective as the predicate devices." This implies a standalone performance evaluation of the device itself (without human interpretation of results, beyond the user reading the display), but the details of this study are not elaborated. The comparison matrix directly addresses the device's inherent capabilities against the predicate.

7. Type of Ground Truth Used:

For the body fat measurement component, the ground truth would typically be established against a recognized gold standard for body composition (e.g., DEXA scan, hydrostatic weighing, or a dual-energy X-ray absorptiometry). For the blood pressure measurement component, the ground truth would typically be established against a medical-grade, validated oscillometric or auscultatory blood pressure measurement device. However, the document does not explicitly state which methods were used as ground truth. It focuses on comparison to a legally marketed predicate device rather than an ultimate gold standard.

8. Sample Size for the Training Set:

The document does not mention the use of a "training set" in the context of an algorithm or AI. This device appears to be based on established bioelectrical impedance analysis (BIA) and oscillometric blood pressure measurement principles, likely using pre-defined algorithms rather than machine learning models that require a distinct training phase.

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

As no training set is indicated, this information is not applicable and is not provided in the document.

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AUG - 1 2003

EXHIBIT 2 Summary of Safety and Effectiveness

Image /page/0/Picture/3 description: The image shows the logo for NIHON SEIMITU SOKKI CO., LTD. The logo is in black and white and features the company name in both Japanese and English. The Japanese name is 日本精密測器株式会社, and the English name is NIHON SEIMITU SOKKI CO., LTD. The logo is simple and modern.

2508-13 Nakago Komochi-Mura, Kitagunma-Gun, Gunma-Ken 377-0293, Japan Phone: +81-0279-20-2311 Fax: +81-0279-20-2411 Contact: Y. Shibata, Chief Engineer

1. Identification of the device

Proprietary-Trade Name: Model WT-20 Wrist Blood Pressure Monitor & Fat Meter Classification Names: DXN, SYSTEM, MEASUREMENT, BLOOD-PRESSURE, NON-INVASIVE, 74 MNW ANALYZER, BODY COMPOSITION Common/Usual Name: Wrist blood pressure monitor/Body fat meter

2. Equivalent legally marketed devices

This product is similar in function and design to the Omron HBF-306 Body Fat Analyzer K011652, and has the blood pressures and pulse rate measurement of Nihon Seimitsu Sokki Co., Ltd. (Nissei) WS-500 Digital Wrist Blood Pressure Monitor K003444.

3. Indications for Use (intended use)

Combination unit for measuring systolic and diastolic blood pressures and pulse rates in adult patients with arm circumference between 4.9" to 8" inches as well as body composition, i.e. estimation of body fat, a noninvasive bioimpedance analyzer for use in estimating the human's body fat volume (mass) and percentage by weight. Age range 10-80 years normal subjects, 18-80 years for athletic subjects.

4. Description of the Device

The Model WT-20 Wrist Blood Pressure Monitor & Fat Meter combines the familiar wrist blood pressure monitor found over the counter in drug stores with a body composition/body fat meter.

5. Safety and Effectiveness, comparison to predicate device

The results of bench and user testing indicate that the new device is as safe and effective as the predicate devices.

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DesignationOMRON Body Fat Analyzer HBF-306K011652Nissei WT-20
Operating PrincipleBioelectrical Impedance Analysis (BIA)SAME (Also measures blood pressure)
DisplayBody fat percentage (4.0 to 50.0%)BMI (7.0 to 90.0)BMI classification (4 levels)5.0 to 50.0 % (body fat)5 to 100 (BMI)BMI classification (4 levels)
Measurement Time7 Seconds5 to 10 seconds
Set rangesHeight: 3'4" to 6'6" (101cm. to 198cm.)Weight: 23lbs. to 440 1/2 lbs (10kg.to220kg.)Age: NORMAL; 10 to 80 years oldATHLETE; 18 to 60 years oldGender: Male / FemaleM1, M2, M3 and M4 or neutral (registration number)22 to 440pounds(weight)36 to 79inches (height)10 to 80 (age)Male or female (sex)
Power supply2 AAA batteries (R03)SAME (Alkaline recommended)
External dimensions197(L) × 128(H) × 49mm(W)93 (W) × 75 (H) × 37.5 (D) mm
Memory9 personal profile memories4 sets of weight, height, age, sex and 10 measurementresults of blood pressure and body fat
WeightApprox.230 g (not including batteries)Approx, 113g (without batteries), 150 g with batteries
Accessories2 AAA batteries for monitor useInstruction manualBody Logic Fitness and Nutrition Guide2 AAA batteries for monitor useInstruction manual

Comparison matrix - new vs. Predicate device 6.

7. Conclusion

After analyzing both bench and clinical testing data, it is the conclusion of Nissei that the "WT-20" Wrist Blood Pressure Monitor and Fat Meter is as safe and effective as the predicate devices, has few technological differences, and has no new indications for use, thus rendering it substantially equivalent to the predicate devices.

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Image /page/2/Picture/1 description: The image shows the seal for the Department of Health & Human Services - USA. The seal is circular and contains the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. In the center of the seal is an image of an eagle with its wings spread. The eagle is facing to the right and has three stripes on its wings.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

AUG - 1 2003

Nihon Seimitsu Sokki Co., Ltd. c/o Mr. Daniel Kamm Regulatory Engineer Kamm & Associates P.O. Box 7007 Deerfield, IL 60015

Re: K031582

Trade Name: Model WT-20 Wrist Blood Pressure Monitor & Fat Meter Regulation Number: 21 CFR 870.2770 Regulation Name: Impedance plethysmograph. Regulatory Class: Class II (two) Product Code: MNW Dated: May 7, 2003 Received: May 21, 2003

Dear Mr. Kamm:

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

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

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act

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Page 2 - Mr. Daniel Kamm

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); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050. This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office of Compliance at (301) 594-4646. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html

Sincerely yours,

W. Zuckertill
Bram D. Zuckerman, M.D.

Director Division of Cardiovascular Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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  1. Indications for Use

KO31582 510(k) Number_________________________________________________________________________________________________________________________________________________________________

Device Name: Nissei Model WT-20 Wrist Blood Pressure Monitor & Fat Meter

Indications for Use: Combination unit for measuring systolic and diastolic blood pressures and pulse rates in adult patients with arm circumference between 4.9" to 8" inches as well as body composition, i.e. estimation of body fat, a noninvasive bioimpedance analyzer for use in estimating the human's body fat volume (mass) and percentage by weight. Age range 10-80 years normal subjects, 18-80 years for athletic subjects.

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use______________________________________________________________________________________________________________________________________________________________ OR Over the Counter Use__ X . (Per 21 CFR 801.109)

X. Qerth

§ 870.2770 Impedance plethysmograph.

(a)
Identification. An impedance plethysmograph is a device used to estimate peripheral blood flow by measuring electrical impedance changes in a region of the body such as the arms and legs.(b)
Classification. Class II (special controls). The device, when it is a body composition analyzer which is not intended to diagnose or treat any medical condition, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 870.9.