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import ExampleCode from '!!raw-loader!@site/../examples/src/tutorials/api-basics/create-fhir-data.ts'; import MedplumCodeBlock from '@site/src/components/MedplumCodeBlock'; import Tabs from '@theme/Tabs'; import TabItem from '@theme/TabItem';
This is a quickstart sample application that introduces some basic FHIR and Medplum concepts.
You will need the following to get started and instructions on how to set this up were covered in the previous article.
- Make sure you have an account and log into Medplum
- Log in and create Client Application
- Save the Client ID and Client Secret, they will be needed to get your sample to run.
These three requirements will need to be in place to connect
{ExampleCode}:::tip Cloning an existing project
If you have an existing project, and want to copy your data to a new environment (for example to a staging environment), this can easily be done using the $clone
operation. For more details ee the Projects guide.
:::
This example represents a common healthcare workflow, creating an order for lab tests (a.k.a ServiceRequest
in FHIR) for patients and when the lab test is complete creating results (a.k.a. Observation
and DiagnosticReport
in FHIR) that correspond to the original ServiceRequest
.
This example will illustrate how to create FHIR object, how to update them, how to link them, and them how to read them back in bulk.
Here is a breakdown of workflow at a high level
- Authenticate with the server using OAuth client credentials flow
- Use FHIR batch request to create a Patient and a ServiceRequest
- The example will use a conditional to only create the Patient if it does not already exist
- The example will link the ServiceRequest to the Patient
- Create an Observation and DiagnosticReport resources
- Read back the DiagnosticReport and Observations
- Use a batch request to read all Observations in one go, versus making multiple requests
The client credentials flow is a type of connection that is used to obtain an access token outside the context of the user.
{ExampleCode}Patient and a ServiceRequest sounds simple, but there are several nuances. If the Patient already exists, a new one should not be created. We also need to ensure that the ServiceRequest is linked to the correct patient.
Creating a Patient if one does not exist uses the conditional create logic in FHIR. In this example, a patient has an Medical Record Number or MRN. If that MRN exists, then a new patient should not be created. In a lab workflow, it is common for a lab to serve patients repeatedly. In this case where there is already a patient in the system, it would be incorrect (and confusing) to make a new patient record.
{ExampleCode}The behavior of the the Patient.identifier
field is important to note. Patient.identifier
usually has a reference string or URL that describes which system that identifier came from. Identifiers are a concept in FHIR which describe the context in which that identifier is generated, for example, and identifier could be a Social Security Number (SSN) or be created by a health system for their own internal purposes. Here is an example of an identifier scheme for the Australian Healthcare system.
We recommend that providers put documentation of their identifier system online for interoperability purposes.
In some cases, you may want to update the resource in place if it already exists in the system, in addition to creating it if it doesn't exist yet. This is accomplished via a combined "update" and "insert" operation: an "upsert".
Provide the current version of the resource and a search query, similar to createResourceIfNoneExists()
.
- If the search query resolves to a single resource, that resource will be updated.
- If it does not find a matching resource, one will be created from the given data.
- If multiple matches are found, an error will be returned. In this case, more specific search criteria are required to unambiguously identify the resource to be updated or created.
Creating a new ServiceRequest also has some nuance to it. ServiceRequests in this context can be thought of as a "requisition for a lab test" and the ServiceRequest.code
specifies what test panel is being ordered. Most labs will have a concept of a test menu and that should indicate which labs should be run for this service request.
Note that there are many fields on the requisition, and filling them in with the right data is crucial. This example is minimal for clarity.
{ExampleCode}If you are using the hosted Medplum service you can see your ServiceRequest
objects here. Similarly, you can see Patients
here.
Once the lab test has been completed and the specimens analyzed, it is time to create a diagnostic report - but it is really important to link that diagnostic report back to the Patient
and the corresponding ServiceRequest
.
To get this to be linked up, you'll need to have the identifiers for the Patient and ServiceRequest that were created in the previous section.
You can then create a diagnostic report using the function below.
{ExampleCode} {ExampleCode}This will create a DiagnosticReport
that is linked to the ServiceRequest
and to the Patient
. If you are using hosted Medplum, you can view all DiagnosticReports
here.
Hopefully this simple lab workflow, "ordering a lab" and "getting a lab report" was a good beginner illustration on getting started with FHIR. We welcome your feedback. Please feel free to file issues or submit pull requests.
This sample is based on a service where data is hosted on Medplum, but for those who need the data stored on premise, we do support self-hosting the backend.