This page is part of the At-Home In-Vitro Test Report (v1.0.0-ballot: STU 1 Ballot 1) based on FHIR R4. . For a full list of available versions, see the Directory of published versions

Implementation Guide

Implementation Guide Overview

This At-Home In-Vitro Test Implementation Guide creates a common framework (e.g. FHIR resources, FHIR value sets, etc.) that will be leveraged by multiple condition-specific At-Home In-Vitro Test use cases. The framework artifacts included in this guide are intended to be use case independent.

Framework Profiles

Rather than creating multiple condition-specific profiles that only differ by value set binding for each type of At-Home In-Vitro Test type, this IG contains a set of framework profiles which conform to US Core Profiles (where available) with At-Home In-Vitro specific constraints and/or extensions. Some of the framework profiles are intended to be used as-is and some are intended to be used as a base with further constraints, mainly bindings to condition-specific value sets. Each profile contains information about which type they are and which elements are expected to be further constrained for a specific use case.

There is a set of example profiles that represent the COVID-19 use case which should act as guidance for implementation of different use cases. These example profiles have been instantiated in the example instances included in the guide.

Framework Profile	Description	Element to Constrain for Specific Use Case	Constraint Type
Bundle - At-Home In-Vitro Test	This profile constrains the Bundle resource for At-Home Sample Tests.	Bundle.entry	Reference to an DiagnosticReport - Home Lab Results constrained to the specific use case
Device - At-Home In-Vitro Test	This profile constrains the Device resource to At-Home Sample Tests.	Use as is for all use cases
DiagnosticReport - At-Home In-Vitro Results	This profile constrains the US Core Diagnostic Report for Laboratory Results profile to At-Home Sample Tests.	DiagnosticReport.result	Reference to an Observation - At-Home In-Vitro Test Result constrained to the specific use case (e.g. Observation - At-Home In-Vitro Test Result - COVID-19)
MessageHeader - At-Home In-Vitro Test Results	This MessageHeader represents the At-Home In-Vitro Test Results being sent from an application server to a health authority.	Use as is for all use cases
Observation - Patient Question Answer	This profile constrains the FHIR Observation Resource to represent an answer given to a question asked of the patient by the app when recording or uploading their test results.	Use as is for all use cases
Observation - At-Home In-Vitro Test Result	This profile constrains the US Core Laboratory Result Observation to At-Home Sample Tests.	Observation.code	Bind to a value set containing the condition-specific test types
		Observation.value	Bind to a value set containing the condition-specific test results
Specimen - At-Home In-Vitro Test	This Specimen profile identifies and describes the specimen used in an At-Home Sample Test.	Specimen.type	Bind to a value set containing the use case specific specimen types

Underlying Specifications

This guide is based on the HL7 FHIR standard and the US Core IG specification, which builds additional capabilities on top of FHIR. This IG is intended to maximize the number of systems that can conform to this guide as well as to allow for easy growth and extensibility of system capabilities in the future.

Implementers of this specification must understand some basic information about the underlying specifications listed above.

FHIR

This IG uses terminology, notations and design principles that are specific to the HL7 FHIR standard. Before reading this implementation guide, it is important to be familiar with the basic principles of FHIR and how to read FHIR specifications. Readers who are unfamiliar with FHIR are encouraged to review the following prior to reading the rest of this implementation guide.

• FHIR overview
• Developer’s introduction (or Clinical introduction)
• FHIR data types
• Using codes
• References between resources
• How to read resource & profile definitions
• Base resource

This implementation guide supports the recently published FHIR R4 version of the FHIR standard to ensure alignment with the current direction of the FHIR standard.

FHIR Resources Used

The table below identifies the specific FHIR Resources and their purposes that are used in this IG.

FHIR Resource	Purpose
Bundle	Used to group resources for submitting results.
Device	Used to represent At-Home In-Vitro tests.
DiagnosticReport	Used to organize the results of an At-Home In-Vitro test.
Observation	Used to represent the results of an At-Home In-Vitro test, presence of related symptoms, symptom onset time.
Specimen	Used to represent type of specimen used in the At-Home In-Vitro test.
Patient	Used to represent the patient taking the At-Home In-Vitro test.
ValueSet	Used to group codes for various uses such as use case specific test types, test results, specimen types etc.
MessageHeader	Used to specify metadata for routing.
Organization	Representing test manufacturers.
Location	Used to represent locations in workflows.
Endpoint	Used to represent routing information.