(When) Will #FHIR replace HL7 v2 messaging?


I’m working in the healthcare domain and has been hearing the FHIR developments for a while. In my hospital setting, we typically have a Patient Registration System, a EMR system, a LIS and RIS system, and some machine interface (Vital Signs, BMI). We are communicating with each other using HL7 V2 standard and is working fine.

My question is, how does the development of FHIR helps in existing interfaces? Do we need to eventually replace these interfaces with FHIR? If yes, all vendors of the respective systems needs to be FHIR ready.

I like to believe that FHIR is for a future expansion packs, and not a move to replace all existing interfaces. Meaning HL7 V2 are expected to stay.  Another question: In HL7, we dealt with messaging in asynchronous mode. But the FHIR standards, we are moving from the messaging world?


This is a pretty frequently asked question – I got it fairly often at HIMSS last week. My standard answer is:

You don’t fix what isn’t broken, so initially, no one will replace v2 messaging interfaces with FHIR interfaces. Instead, institutions will use FHIR on their perimeter, for integration between enterprises.

I say that because FHIR is able to leverage all sorts of web standards, so it’s naturally a better choice than v2 from that point of view alone, and also because this is where all the action currently is, and why would you use v2 now? Most people I hear from are using FHIR in preference to v2 even though FHIR is still a moving target.

But once that’s in place, institutions will increasingly find that what they can do on the perimeter interfaces is constrained by what the internal services can provide – and then they’ll start gradually replacing their v2 interfaces with FHIR interfaces.



  1. Tony Julian says:

    Several things will be needed for V2 to die:
    * It must be removed from government citations, e.g. U.S. Meaningful Use.
    * Vendors or IT department must budget the replacement of existing V2 interfaces using FHIR.
    * Vendors will have to support the replacements for Orders/Observations, ADT.
    * FHIR must mature enough to make it stable for the purposes.

  2. Rene Spronk says:

    As we’ve seen within those countries where HL7v3 was adopted in large scale projects, the use of such a new standard outside of provider organizations does indeed have an affect on the use of HL7v2 within an organization – HL7v2 wasn’t replaced, but its content was enriched and/or constrained to meet the requirement of having to map to HL7v3 (and vice versa). The use of FHIR may have a similar effect.

    Replacement of HL7v2 interfaces may happen at some point in time, but don’t hold your breath.

  3. Dennis says:

    If a health care facility is using FHIR can those with HL7v2 and HL7v3 communicate to it is using the earlier versions.

  4. Dennis says:

    Compatibility between versions of HL7

    If a health care facility is receiving using HL7FHIR can HL7v2 and HL7v3 communicate to it is using these earlier versions.

    • Grahame Grieve says:

      Somewhat- what is in v2 or v3 can be transformed to FHIR and vice versa, but new things in FHIR won’t have a place in v2/v3

  5. Dennis says:

    Is the transformation done by HL7 FHIR, or do we have to have a transformation module built separately

    • Lloyd McKenzie says:

      FHIR is a standard. It doesn’t “do” anything. Implementations will decide what interfaces they want to expose and whether those interfaces are handled by a transformation layer (e.g. an interface engine) or as a native interface that talks directly to their business/persistance layers.

Leave a Reply

Your email address will not be published. Required fields are marked *

question razz sad evil exclaim smile redface biggrin surprised eek confused cool lol mad twisted rolleyes wink idea arrow neutral cry mrgreen


%d bloggers like this: