(196 days)
The MolecuLight i:X is a handheld imaging tool that allows clinicians diagnosing and treating skin wounds, at the point of care, to
- View and digitally record images of a wound, (i)
- Measure and digitally record the size of a wound, and (ii)
- View and digitally record images of fluorescence emitted from a wound when exposed to an excitation light. (iii)
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 gram 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 that proves the MolecuLight i:X device meets them, based on the provided FDA 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The core clinical claim for the MolecuLight i:X related to bacterial identification is: "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 gram as compared to examination of clinical signs and symptoms alone."
While the document doesn't explicitly state quantitative acceptance criteria in the "we will achieve X performance" format, the demonstrated performance serves as the evidence for meeting their stated claim. The crucial part of the performance is the improvement in identifying wounds with relevant bacterial loads.
Acceptance Criteria (Implied by Clinical Claim and Study Results)
| Metric (vs. CSS alone) | Acceptance Threshold (Implied) | Reported Device Performance (CSS + iX vs. CSS) |
|---|---|---|
| Sensitivity Increase | Increase in likelihood of identifying wounds with >10^4 CFU/g bacteria | CSS+iX: 60.98% |
| CSS: 15.33% | ||
| (~4x increase) | ||
| Specificity Change | Maintain acceptable specificity / avoid significant decrease in correctly ruling out bacteria | CSS+iX: 84.13% |
| CSS: 93.65% | ||
| (~9.5% decrease) | ||
| False Positive Rate | 10^4 CFU/g, whose resulting bacterial load determined by conventional microbiological analysis was 10^4 CFU/g): n = 287 |
* Microbiology Negative (10^4 CFU/g) was "quantitative microbiological analysis," which is a lab-based, objective method, not dependent on expert consensus.
4. Adjudication Method for the Test Set
- The document does not describe an adjudication method for the clinical evaluation of CSS or the interpretation of MolecuLight i:X images. It compares these clinical assessments directly against the quantitative microbiological analysis. This suggests that individual clinicians' interpretations were the data points, rather than a consensus interpretation.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- A formal MRMC study is not explicitly mentioned as having been performed. The study evaluates the likelihood that clinicians can identify wounds, comparing performance with and without the device. While it involves multiple clinicians, it's presented as a direct comparison of the combined CSS+iX approach versus CSS alone, rather than a statistical comparison of reader performance improvement.
- Effect Size:
- The sensitivity for identifying high bacterial loads increased from 15.33% (CSS alone) to 60.98% (CSS + iX). This is a substantial increase, making the device significantly more likely to flag relevant wounds.
- The specificity decreased from 93.65% (CSS alone) to 84.13% (CSS + iX). This indicates a trade-off where more wounds were incorrectly identified as having high bacterial loads with the device, but the report explicitly states this increase in false positives was "10^4 CFU per gram). This is an objective and laboratory-confirmed ground truth, considered a strong reference standard for bacterial burden.
8. Sample Size for the Training Set
- The document does not specify a separate training set or its size. This is typical for a medical device that provides direct imaging for human interpretation, rather than a machine learning algorithm that is "trained" on data. The clinical study described here functions as the pivotal performance validation.
9. How Ground Truth for the Training Set was Established
- As no separate training set or AI/ML training is indicated, this point is not applicable. The ground truth for the clinical study was established by quantitative microbiological analysis of wound samples.
§ 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.