K Number
K203473
Device Name
SOZO
Manufacturer
Date Cleared
2021-04-19

(145 days)

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

The SOZO Body Fluid Analyzer is intended for adult patients living with heart failure. This device is intended for use, under the direction of a physician, for the noninvasive monitoring of patients with fluid management problems suffering from heart failure. Data from the device should be considered in conjunction with other clinical data.

Device Description

The SOZO system consists of a connected hand and footplate with built-in stainless steel electrodes, paired with an Android tablet over Bluetooth connection. An app ("SOZOapp"), supplied with the tablet, controls the functionality of the hardware and supplies the bioimpedance measurement data to a database ("MySOZO") managed on an external cloudhosted database.

Measurements require the patient to make contact with bare hands and feet on stainless steel electrodes. The measurement takes about 30 seconds, during which the SOZO® system applies small levels of electrical energy (200uA RMS) to the body across 256 frequencies spaced from 3kHz to 1000kHz and measures the resulting voltage levels.

AI/ML Overview

The provided text is a 510(k) summary for ImpediMed Limited's SOZO device. It outlines the regulatory review process, device description, technological characteristics, and performance data. However, it does not contain the specific details about acceptance criteria, the study design (like sample sizes for test and training sets, data provenance), ground truth establishment, expert qualifications, or MRMC comparative effectiveness studies that would typically be found in a clinical study report or a more detailed performance section of a 510(k) submission.

The document primarily focuses on demonstrating substantial equivalence to a predicate device (ImpediMed Limited's SOZO, K193410) through technical and safety testing, rather than a clinical performance study evaluating the diagnostic accuracy or effectiveness of a new AI-driven diagnostic feature.

The key change described in this 510(k) is a software modification: "Modification to SOZOapp Fluid Analysis module, renaming it as the 'HF-Dex' module and incorporating a set of normative reference ranges to aid the clinician in their fluid management of patients living with heart failure." This suggests the change is primarily about presenting existing data with new reference points for clinical interpretation, not necessarily about a new algorithm for fluid analysis that would require extensive clinical validation as requested in the prompt.

Given the information provided, I cannot fulfill all parts of your request. The document describes:

  • Performance Data in general terms: "The SOZO system has gone through appropriate testing per design controls to confirm functionality and performance of the indications." This refers to:
    • Electrical safety/EMC (IEC 60601)
    • Software V&V (ISO 62304)
    • Biocompatibility (ISO 10993)
    • Functional performance: "performance testing was undertaken using both fixed loads and human volunteers comparing modified to predicate SOZO measurements to demonstrate that outputs remained consistently accurate and precise." This last point is the closest to a performance study, but it's focused on accuracy and precision of measurements (bioimpedance parameters, extracellular fluid, intracellular fluid, and total body water) compared to the predicate device, not on the diagnostic accuracy of the "HF-Dex" module for managing heart failure fluid.

Therefore, many sections of your request cannot be answered from the provided text.

Here's what can be extracted and inferred, along with the limitations:

1. A table of acceptance criteria and the reported device performance:

The document broadly states: "The software was verified and validated to meet acceptance criteria and perform as intended." And for functional performance: "to demonstrate that outputs remained consistently accurate and precise." However, specific quantitative acceptance criteria and the corresponding reported numerical performance (e.g., specific accuracy percentages, precision values, or ranges) are not provided.

Acceptance Criteria (Stated or Inferred)Reported Device Performance (Specificity Lacking)
Electrical Safety / EMC compliance (IEC 60601)Met requirements; CB certificate granted.
Software V&V compliance (ISO 62304)Verified and validated to meet acceptance criteria and perform as intended. Specific metrics are not provided.
Biocompatibility (ISO 10993)Passed testing with no failures reported.
Functional Performance (Accuracy & Precision)Outputs remained consistently accurate and precise when comparing modified to predicate SOZO measurements. Specific numerical values are not provided.
Substantial Equivalence to Predicate K193410Demonstrated to be as safe and effective, and performs as well as or better than the predicate device.
HF-Dex Module aiding clinician fluid managementThe document implies this is achieved by "incorporating a set of normative reference ranges." No specific performance metrics for this clinical utility are provided.

Missing Information for a Detailed AI/Diagnostic Performance Study:

Since the document describes a software modification primarily related to displaying normative reference ranges and not a new diagnostic algorithm requiring an AI performance study, the following information is not present:

2. Sample size used for the test set and the data provenance: Not applicable in the context of this 510(k) summary, as it doesn't describe a clinical performance study for a new diagnostic algorithm. The "human volunteers" for functional performance testing are mentioned, but no sample size or provenance is given.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable, as there's no diagnostic test set with ground truth described.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set: Not applicable.

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: Not applicable. This change isn't an AI-assistance feature in the sense of image interpretation or complex diagnostic aid, but rather new reference ranges for an existing measurement.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable. The "HF-Dex" module seems to be a display enhancement to an existing measurement device, and its performance is tied to the underlying bioimpedance measurements, which are assessed against the predicate's measurement accuracy, not as a standalone diagnostic algorithm.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.): For the functional performance of the bioimpedance measurements, the ground truth indirectly relies on the established accuracy and precision of the predicate device (K193410) and potentially comparison to known physical properties via "fixed loads." For the "HF-Dex" module providing normative ranges, the "ground truth" would be the clinical standard or source of those normative ranges, which is not detailed here.

8. The sample size for the training set: Not applicable. This document does not describe a machine learning algorithm that requires a training set. The "HF-Dex" module incorporates "normative reference ranges," which implies pre-defined medical standards or clinical data, not a learned model from a training set.

9. How the ground truth for the training set was established: Not applicable.

In summary, this 510(k) notification focuses on demonstrating that modifications to an existing device (SOZO) – specifically, a software update incorporating new normative reference ranges – do not raise new safety or effectiveness concerns and maintain substantial equivalence to the predicate. It does not describe a clinical performance study of a new diagnostic algorithm involving AI or a comprehensive test set with established ground truth as you've outlined in your request.

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April 19, 2021

ImpediMed Limited Reuben Lawson Senior Director, Regulatory Affairs and Clinical ImpediMed Inc. 5900 Pasteur Court, Unit 125 Carlsbad, California 92008

  • Re: K203473 Trade/Device Name: SOZO Regulation Number: 21 CFR 870.2770 Regulation Name: Impedance plethysmograph Regulatory Class: II Product Code: DSB Dated: March 15, 2021 Received: March 17, 2021
    Dear Reuben Lawson:

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

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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 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 devicerelated 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/guidanceregulatory-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 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-devices/medical-devicesafety/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/medicaldevices/device-advice-comprehensive-regulatory-assistance/contact-us-division-industry-andconsumer-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.

Carolyn Y. Neuland, Ph.D. Assistant Director DHT3A: Division of Renal, Gastrointestinal, Obesity and Transplant Devices OHT3: Office of GastroRenal, ObGyn, General Hospital and Urology Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

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DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Indications for Use

Form Approved: OMB No. 0910-0120 Expiration Date: January 31, 2017 See PRA Statement on last page

510(k) Number (if known)

K203473

Device Name

SOZO®

Indications for Use (Describe)

The SOZO Body Fluid Analyzer is intended for adult patients living with heart failure.

This device is intended for use, under the direction of a physician, for the nonitoring of patients with fluid management problems suffering from heart failure. Data from the device should be considered in conjunction with other clinical data.

Type of Use (Select one or both, as applicable)

X 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.

The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:

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510(k) SUMMARY

ImpediMed's SOZO

Submitter

ImpediMed LimitedUnit 150 Parker CourtPinkenba, Qld 4008Australia
Phone:760 585 2104
Facsimile:760 804 9425
Contact Person:Reuben Lawson
Date Prepared:April 19, 2021
Name of Device:SOZO®
Common or Usual NameBody Fluid Analyzer
Regulation Number21 CFR §870.2770
Regulation NameImpedance Plethysmograph
Regulatory ClassII
Product Code:DSB
Predicate Device:ImpediMed Limited's SOZO (K193410)

Purpose of the Traditional 510(k) Notice

The purpose of the 510(k) is to clear modifications to the device including updates to software and labeling.

Indications for Use

The SOZO Body Fluid Analyzer is intended for adult patients living with heart failure. This device is intended for use, under the direction of a physician, for the noninvasive monitoring of patients with fluid management problems suffering from heart failure. Data from the device should be considered in conjunction with other clinical data.

Device Description

The SOZO system consists of a connected hand and footplate with built-in stainless steel electrodes, paired with an Android tablet over Bluetooth connection. An app ("SOZOapp"),

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supplied with the tablet, controls the functionality of the hardware and supplies the bioimpedance measurement data to a database ("MySOZO") managed on an external cloudhosted database.

Measurements require the patient to make contact with bare hands and feet on stainless steel electrodes. The measurement takes about 30 seconds, during which the SOZO® system applies small levels of electrical energy (200uA RMS) to the body across 256 frequencies spaced from 3kHz to 1000kHz and measures the resulting voltage levels.

Technological Characteristics

Bioimpedance spectroscopy is the technological principle for both the subject and predicate devices. The subject and predicate devices are based on the following same fundamental technological elements:

o Use of electrodes to take measurements; two 'drive' and two 'sense' channels are used to measure each side of the body

ം 'Drive' channels deliver very low levels of current (200µa RMS) across 256 frequencies logarithmically spaced from 3kHz to 1000kHz;

ം 'Sense' channels measure current (I), voltage (V) and phase angle (Ph), and calculates three bioimpedance parameters: impedance (Z), resistance (R) and reactance (Xc) to estimate extracellular fluid, intracellular fluid and total body water.

o Data is stored in and accessed from a cloud-based database (MySOZO) using a web browser interface. SOZO is controlled through an Android app ("SOZOapp") on a supplied tablet, which is paired to the SOZO hardware over Bluetooth connection, and connects with the MySOZO database over Wi-Fi.

Performance Data

The SOZO system has gone through appropriate testing per design controls to confirm functionality and performance of the indications.

Electrical safety/EMC: testing was performed according to the requirements set forth in IEC 60601 (subparts -1. -1-2. and -1-6). It was determined that the SOZO device meets electrical safety and EMC requirements, and CB certificate was granted for the system.

Software V&V: the same level of concern software documentation as the predicate device was created and testing performed in accordance with ISO 62304. The software was verified and validated to meet acceptance criteria and perform as intended.

Biocompatibility: testing was performed by an accredited third party according to the requirements set forth in ISO 10993 for a low risk, limited contact device. It was determined that the SOZO system passed biocompatibility testing with no failures reported.

Functional performance: performance testing was undertaken using both fixed loads and human volunteers comparing modified to predicate SOZO measurements to demonstrate that outputs remained consistently accurate and precise.

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Substantial Equivalence

The modified SOZO has the same intended use and similar indications, principles of operation, and technological characteristics as its predicate device. The following difference in the modified SOZO device's technological characteristics do not raise any new questions of safety or effectiveness:

  • Modification to SOZOapp Fluid Analysis module, renaming it as the 'HF-Dex' module and incorporating a set of normative reference ranges to aid the clinician in their fluid management of patients living with heart failure.

Thus, the modified SOZO is substantially equivalent to its predicate devices.

Conclusions

Testing discussed above demonstrates that the modified SOZO device is as safe and effective, and performs as well as or better than the predicate device.

§ 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.