FHIR (Fast Healthcare Interoperability Resources) is a data interoperability standard and specification, made for the purpose of exchanging medical and healthcare data. In the age of digitisation, sharing of data while keeping standards and interoperability intact are becoming increasingly important. Health Interoperability is the most important word in this context as it describes why this protocol is for. The word "Fast" in convey that this standard is fast to learn and adopt. You won't need an expertise in programming to be successful with FHIR. You can quickly learn and adopt FHIR which is a fundamental aim of FHIR standard.
In short FHIR can be explained in five points as follows.
A robust data model for describing health and administrative data.
A restful API for interacting with that data using either JSON or XML.
A set of open-source tools to implement and test FHIR applications.
A collection of FHIR Servers around the world that you can interact with.
A community of implementers working together.
In the early 2000s, the simple task of storing and sharing data was a challenging task. This story was true for healthcare data as well. Prior to the FHIR, HL7v2 and HL7v3 were the standards used for healthcare. HL7v2 was one of the initial standards developed by HL7, the company which develops FHIR. But its nature of being too information-dense and being complicated led to the development of a newer standard called HL7v3. Although HL7v3 was a great effort and had many sophisticated features, it never took off since it was not able to keep up with the technology of that time. Basic Technology was quite the barrier to achieving any kind of interoperability in both the cases of v2 and v3. For the most part, the only part of HL7 v3 that remains widely adopted today is the Clinical Document Architecture (CDA). CDA allows for metadata standardisation and various clinical data points. However, as implied by the name, CDA is only specific to clinical data. FHIR was created as a response to these old technologies to meet modern needs for data and interoperability.
Electronic Health Record (EHR) vendors like DIPS, Epic and Cerner, Apple, Microsoft, Google... etc. are widely using FHIR. The reasons for this are two-fold: first, because FHIR is based on modern web technologies that software developers can easily use without in-depth healthcare domain knowledge. And second, because companies are starting to recognize the multitude of benefits of FHIR.
Fhir is adopted by many developed countries in the world and USA takes the lead. The following map shows that adoption of technology enabled with FHIR is widespread across the US. It shows that hospitals in most regions are at or above the national 84% average with some regions showing that 100% of hospitals have deployed technology enabled with FHIR. It’s important to note that hospitals in some regions lag behind, such as in the southwest and mountain west.
Resources are the basic building blocks of the FHIR standard. A FHIR resource is an entity used to map real-life data which approximately resembles to a "class" in object oriented programming context. It is basically picked up from the HTTP spec which basically describes the entire web in terms of these addressable fetchable resources. FHIR basically represents everything as resources and defines a health record as a collection of resources. Eg: Health Record may store the information of the condition of the patient, in FHIR this may be stored as the Condition and Patient resource. Each resource can be represented in different forms like XML and JSON.
Each resource in FHIR has some narrative and use case behind it. A narrative in FHIR may represent a situation, some actors, and other entities related to healthcare. FHIR defines a wide variety of resources to start with. The fhir resource list provided by HL7 can be accessed here.