(89 days)
The MolecuLight i:X is a handheld imaging tool that allows clinicians diagnosing and treating skin wounds, at the point of care, to
(i) View and digitally record images of a wound.
(ii) Measure and digitally record the size of a wound, and
(iii) View and digitally record images of fluorescence emitted from a wound when exposed to an excitation light.
The fluorescence image, when used in combination with clinical signs and symptoms, has been shown to increase the likelihood that clinicians can identify wounds containing bacterial loads >104 CFU per grams as compared to examination of clinical signs and symptoms alone. The MolecuLight i:X device should not be used to rule-out the presence of bacteria in a wound.
The MolecuLight i:X does not diagnose or treat skin wounds.
The MolecuLight i:X Imaging Device is a handheld medical imaging device comprised of a high-resolution color LCD display and touch-sensitive screen with integrated optical and microelectronic components. MolecuLight i:X uses its patented technology to enable real-time standard digital imaging and fluorescence imaging in wounds and surrounding healthy skin of patients as well as wound area measurements.
Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided FDA 510(k) summary for the MolecuLight i:X:
The MolecuLight i:X device is an autofluorescence detection device for general surgery and dermatological use. The 510(k) summary details a modification to the device's labeling to clarify the relationship between cyan fluorescence and the increased likelihood of Pseudomonas aeruginosa bacterial loads. The study's purpose is to demonstrate that this additional labeling statement does not raise new questions of safety or efficacy and is supported by existing clinical data.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly tied to the performance metrics of the device in identifying bacterial loads, specifically Pseudomonas aeruginosa and Total Bacterial Load (TBL), as established in the original K191371 clearance. The current submission's goal is to demonstrate that the expanded labeling around cyan fluorescence's association with P. aeruginosa is supported by the data and does not alter the previous safety and effectiveness profile.
The performance is reported in terms of sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), and Likelihood Ratio for different fluorescence signatures (Cyan, Red, Red or Cyan) in detecting bacterial loads.
| Performance Metric Category | Specific Metric | Acceptance Criteria (Implied from K191371 and consistency) | Reported Device Performance (95% CI) for Cyan Fluorescence and P. aeruginosa ≥ 10^4 CFU/g |
|---|---|---|---|
| Detection of Pseudomonas aeruginosa (Pa) at Species Specific Levels ≥ 10^4 CFU/g (Table 2 & 3) | Sensitivity | Clinical utility demonstrated by previous clearance | 43.75% (26.26, 62.34) |
| Specificity | Clinical utility demonstrated by previous clearance | 94.97% (91.96, 97.10) | |
| Positive Predictive Value (PPV) | Clinical utility demonstrated by previous clearance | 46.67% (28.34, 65.67) | |
| Negative Predictive Value (NPV) | Clinical utility demonstrated by previous clearance | 94.38% (91.26, 96.63) | |
| Likelihood Ratio | Clinical utility demonstrated by previous clearance | 8.70 (4.69, 16.14) | |
| Detection of Total Bacterial Load (TBL) at Levels ≥ 10^4 CFU/g (Table 4) | PPV for Cyan FL | Clinical utility demonstrated by previous clearance | 0.967 (0.828, 0.999) |
| Likelihood Ratio for Cyan FL | Clinical utility demonstrated by previous clearance | 6.366 | |
| Detection of TBL at Levels ≥ 10^4 CFU/g in Absence of Pseudomonas aeruginosa (Table 5) | PPV for Cyan FL | Clinical utility demonstrated by previous clearance | 0.938 (0.698, 0.998) |
| Likelihood Ratio for Cyan FL | Clinical utility demonstrated by previous clearance | 3.706 |
Note: The document states "The additional labeling statement does not raise different questions of safety or efficacy. Retrospective analysis has demonstrated the safety and effectiveness of MolecuLight i:X with regards to the additional labeling statement." This implies that the acceptance criteria are met if the performance metrics continue to support the device's utility in identifying bacterial loads and the new labeling is consistent with the observed data.
2. Sample Size and Data Provenance
- Sample Size for Test Set: Data from 350 patients were retrospectively analyzed.
- Data Provenance: The document does not explicitly state the country of origin but refers to "retrospective analysis" of existing clinical study data. Given MolecuLight Inc. is based in Toronto, Canada, and the clinical study was "reported in support of K191371", it is likely the data was collected in either Canada or the US, or potentially a multi-site international study. The study was retrospective.
3. Number of Experts and their Qualifications
The document does not specify the number of experts used to establish the ground truth for the test set, nor does it explicitly state their qualifications. The interpretation of "fluorescence image, when used in combination with clinical signs and symptoms" suggests that the ground truth was established by clinicians based on the convergence of factors, potentially including microbiological culture results (as indicated by CFU/g measurements).
4. Adjudication Method for the Test Set
The document does not describe any adjudication method for the test set. Given that the analysis is "retrospective analysis" of existing clinical study data, the ground truth was likely established as part of the original study design.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not performed for this 510(k) submission. This submission is a "Real-World Data" (retrospective analysis) supporting a labeling change for a previously cleared device, not a new device clearance or a comparative effectiveness study with human readers. The document states: "The fluorescence image, when used in combination with clinical signs and symptoms, has been shown to increase the likelihood that clinicians can identify wounds containing bacterial loads >10^4 CFU per grams as compared to examination of clinical signs and symptoms alone." This sentence refers to a finding from the original K191371 clearance, not a new MRMC study in this submission.
6. Standalone (Algorithm Only) Performance
This device, the MolecuLight i:X, is an imaging tool used by clinicians to view and record images of fluorescence. It is not an AI algorithm that generates a diagnosis or interpretation autonomously. Therefore, a standalone (algorithm only) performance study was not applicable or performed in the context of this 510(k). The device provides visual information (fluorescence images) that clinicians interpret in conjunction with clinical signs and symptoms.
7. Type of Ground Truth Used
The ground truth for the test set appears to be microbiological culture results (bacterial loads measured in CFU/g) combined with clinical assessment. The specific phrases "identify wounds containing bacterial loads >10^4 CFU per grams" and "Pseudomonas aeruginosa at Species Specific Levels ≥ 10^4 CFU/q" clearly indicate that quantitative bacterial culture was the definitive ground truth for bacterial presence and load.
8. Sample Size for the Training Set
The document does not describe a training set in the context of an AI/algorithm. The "study" described is a retrospective analysis of previously collected clinical data to support a labeling claim for a medical device. If there was any machine learning involved (which is not directly implied for this device's function as an imaging tool), that would have been part of the original K191371 submission and is not detailed here.
9. How the Ground Truth for the Training Set was Established
As no training set (in the context of an AI/ML algorithm) is described, this question is not applicable based on the provided document. The device's function described (capturing and displaying fluorescence) implies it is a viewing tool, not an AI-powered diagnostic algorithm requiring a training phase for its output beyond the initial development of its optical and imaging capabilities.
§ 878.4550 Autofluorescence detection device for general surgery and dermatological use.
(a)
Identification. An autofluorescence detection device for general surgery and dermatological use is an adjunct tool that uses autofluorescence to detect tissues or structures. This device is not intended to provide a diagnosis.(b)
Classification. Class II (special controls). The special controls for this device are:(1) In vivo testing under anticipated conditions of use must characterize the ability of the device to detect autofluorescent signals from tissues or structures consistent with the indications for use.
(2) The patient-contacting components of the device must be demonstrated to be biocompatible.
(3) Performance testing must demonstrate the electromagnetic compatibility and electrical, mechanical, and thermal safety of the device.
(4) Software verification, validation, and hazard analysis must be performed.
(5) Performance testing must demonstrate the sterility of patient-contacting components of the device.
(6) Performance testing must support the shelf life of device components provided sterile by demonstrating continued sterility and package integrity over the labeled shelf life.
(7) Performance testing must demonstrate laser and light safety for eye, tissue, and skin.
(8) Labeling must include the following:
(i) Instructions for use;
(ii) The detection performance characteristics of the device when used as intended; and
(iii) A shelf life for any sterile components.