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A bioimpedance spectroscopy device for use on adult human patients, utilizing impedance ratios that are displayed as an L-Dex ratio that supports the measurement of extracellular fluid volume differences between the limbs and is presented to the clinician on an L-Dex scale as an aid to their clinical assessment of unilateral lymphedema of the arm and leg in women and the leg in men.

The device is only indicated for patients who will have or who have had lymph nodes, from the axillary and pelvic regions, either removed, damaged or irradiated.

Lymphedema Analysis PC Software - an optional PC software package that is intended to be used only with the ImpediMed L-Dex U400 device for uploading data on to the PC from the L-Dex U400, processing and analyzing of bioimpedance measurements.

The ImpediMed L-Dex U400 Extra Cellular Fluid Analysis device is a battery powered bioimpedance spectroscopy device operating in tetra-polar mode via a set of leads that are attached to self-adhesive skin electrodes by means of alligator clips. The subject device accurately measures current, voltage and phase angle, and cakulates three bioimpedance parameters: impedance (Z), resistance (R) and reactance (Xc). These measurements and calculations are used to estimate extracellular fluid ratios, and calculate the Lymphedema Index or L-Dex.

The L-Dex U400 measures bioimpedance parameters over a frequency range of 4 - 1000 kHz with 256 data points. An on-screen graph displays the raw measured data in the form of a resistance vs. reactance complex impedance plot. These bioelectrical parameters are then used in algorithms to give an L-Dex value for the affected compared to the unaffected limb.

Measured impedance ratios (L-Dex values) and normal ranges are shown on the device immediately after measurement and stored for later reference. Measured data may be transferred to the ImpediMed Impsoft database software. The Impsoft software adds extra functionality and ease of data management, including viewing patient histories and printing reports.

Here's an analysis of the provided text regarding the ImpediMed L-Dex U400 and its performance claim, structured according to your request:

1. Table of Acceptance Criteria and Reported Device Performance

Based on the provided text, the submission is a 510(k) for substantial equivalence to a predicate device (K100811), not a de novo clearance with defined performance acceptance criteria. The "Performance Data" section explicitly states: "The company has provided an overview of reports in the literature that describes the use of the device for its indications for use." This indicates that the submission relies on existing literature and comparison to its own previously cleared device, rather than new, primary performance studies with explicit acceptance criteria for the current submission.

Therefore, since no specific acceptance criteria for this 510(k) submission are mentioned, and the performance data refers to an "overview of reports in the literature," a table of acceptance criteria and reported performance cannot be generated from the given text. The FDA's substantial equivalence decision is based on the new device being "as safe and effective" as the predicate.

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

The document does not detail any specific de novo test set for this 510(k) submission. It states: "Performance data demonstrate that the subject device is as safe and effective as the company's predicate device for the proposed indications for use." This implies reliance on data from the predicate device's clearance (K100811) or general literature, but no sample size or data provenance (country, retrospective/prospective) for a new test set is provided in this document.

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

Since no de novo test set or specific performance study is detailed for this 510(k) in the provided text, there is no information on the number of experts or their qualifications used to establish ground truth.

4. Adjudication Method for the Test Set

As no de novo test set or specific performance study is detailed, no adjudication method is mentioned in the provided text.

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

The document does not mention any MRMC comparative effectiveness study being performed for this 510(k) submission, nor does it discuss the effect size of human readers with or without AI assistance. The device is a bioimpedance spectroscopy device, not an image-reading AI.

6. Standalone (Algorithm Only) Performance Study

The information provided suggests that the device's function is to measure bioelectrical parameters and calculate an L-Dex value, which is then "presented to the clinician on an L-Dex scale as an aid to their clinical assessment." This implies human-in-the-loop use. However, the document does not detail a standalone performance study in the context of this 510(k) submission. The performance claim is for substantial equivalence to its predicate.

7. Type of Ground Truth Used

The document focuses on substantial equivalence based on technological characteristics and intended use. It does not describe the type of ground truth (e.g., pathology, outcomes data, expert consensus) used for any specific performance study related to this 510(k) submission. Any "ground truth" would likely refer to the data used in the "reports in the literature" that describe the use of the device.

8. Sample Size for the Training Set

The document does not mention a training set or its sample size. This is a 510(k) submission for a device, not a new AI algorithm development requiring a distinct training phase to develop the L-Dex algorithm itself. The algorithms are already established in the predicate device.

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

Since no training set is mentioned in the context of this 510(k) submission, there is no information on how its ground truth was established. The L-Dex algorithm itself would have been developed and validated previously, and those details are not part of this specific 510(k) summary.

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