We’re all familiar with FHIR’s Patient resource.
It sits at the center of the spider’s web.
But what do you know about the Patient link element?
Link is an “Is-Modifier” element. This means that it cannot safely be ignored. If it’s populated, your code needs to understand it.
It’s defined as a “Link to another Patient resource that concerns the same actual person.”
The link.type is where things gets interesting. It has 4 possible values:
‘replaced-by’ means the link points to another Patient resource that supersedes this one. That’s a problem.
‘replaces’ means it’s the current active Patient record and the linked resource is no longer active. Ok then.
‘refer’ means that while the current Patient resource is valid, the linked resource is the main source of information about the patient. Another problem.
‘seealso’ is more vague: The linked resource contains information about the same person that might overlap or contradict the current resource. Maybe a problem, maybe not.
The message here is that if a Patient link exists, your code needs to handle it. Any link.type value other than “replaces” means the Patient resource may not be valid.
More about the Patient link type element: http://hl7.org/fhir/R4/valueset-link-type.html#expansion
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