Technical specifications
Product form and deployment
The device is software only. It is hosted and operated by the manufacturer as a cloud service and is accessed over the internet by the care provider's system. There is nothing to install on the user's premises or on the user's device, and the user does not deploy, configure or update the software.
An internet connection is required. The device cannot be used without one, which means it cannot be used without access to these instructions for use either.
Interface
The device is integrated through an HTTPS application programming interface. The care provider's system sends images and, optionally, additional data, and receives clinical data in return.
| Item | Specification |
|---|---|
| Integration method | HTTPS application programming interface |
| Request and response format | JSON |
| Image transmission | Images are supplied as base64-encoded content inside the JSON request |
| Output resource | FHIR DiagnosticReport, with a status of preliminary |
| Authentication | A unique, non-transferable API key, supplied in the headers of each request |
The endpoints available to version 2.1 of the device are:
https://ai.legit.health/v2/legit_health/predicthttps://ai.legit.health/v2/legit_health/diagnosis_supporthttps://ai.legit.health/v2/legit_health/severity_assessment
The request and response schemas for each endpoint, and the meaning of every field returned, are described in the Installation manual.
Input requirements
The device analyses what is visible in the image supplied to it, so the quality of that image determines the quality of the output.
- The image must show a skin structure. The device checks this itself and reports the result, as described in Domain validation.
- The image must be in focus, adequately lit, and taken close enough to the skin structure for it to occupy a significant part of the frame.
- The image must not have been artificially edited, compressed or resized. Images downloaded from the internet, or received through messaging applications, are frequently compressed and are not suitable.
The full guidance on image acquisition, including worked examples of correct and incorrect images, is in How to take pictures.
Quality checks performed by the device
Alongside the clinical output, the device returns information about the suitability of the image it received. The care provider's system should surface this information to the user, because it indicates when an output should be treated with caution.
| Field | Meaning |
|---|---|
isDermatologyDomain | Whether a skin structure was detected in the image |
hasEnoughQuality | Whether the image is of sufficient quality for the clinical algorithms |
score | A quality score for the image supplied |
Image capture equipment
The device does not require any particular make or model of camera. It is used with the cameras that healthcare professionals and patients already have, typically a smartphone camera, a digital camera or a dermatoscope. What matters is that the resulting image meets the input requirements above.