# Underlying Technologies - PACIO Transitions of Care Implementation Guide v1.0.0

* [**Table of Contents**](toc.md)
* **Underlying Technologies**

## Underlying Technologies

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| *Page standards status:*[Informative](http://hl7.org/fhir/R4/versions.html#std-process) |

### Fast Healthcare Interoperability Resources

Based on the [HL7 FHIR](http://hl7.org/fhir/R4/index.html) standard, this implementation guide uses terminology, notations, and design principles that are specific to FHIR. Implementers of this specification therefore need to understand some basic information about this specification.

Before reading this implementation guide, it's important to be familiar with some of the basic principles of FHIR as well as general guidance on how to read FHIR specifications. Readers who are unfamiliar with FHIR are encouraged to read the following prior to reading the rest of this implementation guide.

* [FHIR overview](http://hl7.org/fhir/R4/overview.html)
* [Developer's introduction](http://hl7.org/fhir/R4/overview-dev.html)
* [FHIR data types](http://hl7.org/fhir/R4/datatypes.html)
* [Using codes](http://hl7.org/fhir/R4/terminologies.html)
* [References between resources](http://hl7.org/fhir/R4/references.html)
* [How to read resource & profile definitions](http://hl7.org/fhir/R4/formats.html)
* [Base resource](http://hl7.org/fhir/R4/resource.html)
* [Security](http://hl7.org/fhir/R4/security.html)
* [Security Labels](http://hl7.org/fhir/R4/security-labels.html)

This implementation guide supports the [R4](http://hl7.org/fhir/R4/index.html) version of the FHIR standard and builds on the [US Core Implementation Guide](http://hl7.org/fhir/us/core) and implementers need to familiarize themselves with the profiles in that guide. Implementers should also familiarize themselves with the FHIR resources used within the guide:

* [DocumentReference](http://hl7.org/fhir/R4/documentreference.html)
* [Composition](http://hl7.org/fhir/R4/composition.html)
* [Observation](http://hl7.org/fhir/R4/observation.html)

