All FHIR resources have a Meta element containing metadata about the resource. Some attributes are updated by the server, others are populated by the app constructing the resource.
Here’s a look inside the Meta element.
1. versionId
This is an ID that identifies a saved version of the resource on the FHIR server. Many servers use a GUID here, others use an integer. But it’s a string value, so don’t write code against this assuming a sequential integer, regardless of what the server does.
2. lastUpdated
The date and time that the resource was last updated, populated by the server. Most of us will have used this as a sort parameter in query strings to get the most recently updated resources.
3. source
I’ve seldom seen this URI value populated, but when it is it identifies the source of the data. It’s often used in place of a Provenance resource, which can fulfil a similar function.
4. profile
A list of FHIR profiles that the resource must conform to. This can be populated by the sender, or populated dynamically by some middleware before the request reaches the FHIR server. Depending on how the server is configured and how the request is structured, it will usually trigger a validation of the resource against the specified profiles.
5. security
A list of Security Labels applied to the resource. Not used as often as it could be, and often ignored when it shouldn’t be! Your app needs to handle Security Labels, especially if you’re receiving Bundles from external sources.
More: https://darrendevitt.com/do-you-know-what-security-labels-are-in-fhir/
6. tags
Again, seldom used. Tags connect resources to processes and workflows. They can be ignored by consuming applications which might account for their sparse use.
The image was generated by ChapGPT, with a little prompting.
More about the Meta element: http://hl7.org/fhir/resource.html#Meta
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