(145 days)
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.
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.
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 K193410 | Demonstrated to be as safe and effective, and performs as well as or better than the predicate device. |
| HF-Dex Module aiding clinician fluid management | The 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.
§ 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.