Health Level 7 (HL7) – The Need & The Limitations

To understand Health Level Seven (HL7), let’s highlight the issues that plague health care IT environments.

Let’s start at the beginning, the government rolled out the Meaningful Use Program which financially incentivizes providers to adopt EHR technology and exchange health care data with external organization/applications to create a national connected healthcare information exchange network (HIE).

Interestingly enough, many providers thought past the HIE model to meet current needs. Instead, they have took it upon themselves to communicate with affiliated providers within their network rather than those HIEs, focusing on their own interoperability structure than a national one. For instance, most health systems today have multiple applications installed and running at once. This includes, EHRs, lab, radiology and billing systems typically from different vendors. However, as you can now imagine, these systems were designed to cater towards flexibility within its own environment over the ability to integrate with other systems outside of it. This type of design creates silos within the healthcare IT environments rendering true national interoperability non-existent.

Along with the above government mandate, these are inherently the issues that HL7 v2 aims to solve (internal network and external application integrations). Using HL7v 2, data can be exchanged by these separate systems in a agreed upon standard fashion.

Typical Workflow

Data exchanged between systems follow the usually workflow using HL7v2:

1. A healthcare provider documents and types in data to a EHR provided by an vendor
2. That vendor/EHR allows data to leave the system in a HL7v2 or CDA document
3. The data is sent over an interface and received by the target application.
4. That target application parses the information based on the standards and imports it to the database.

It is worth mentioning that this usually happens using point-to-point interfaces. These interfaces tend to follow push models where patient data is pushed each time an update is made within that application. Real time approaches such as asking for the status of patient’s orders , room, vitals or location is not possible with HL7 v2 messages.  In fact, HL7 v2 interfaces take several steps to find needed information as they push data transacation from the database. In the below example, an HL7 ADT interface will push information everytime a patients information is updated:

Admitting a Patient Example

1. Look for patient ID in the index
2. Search for a bed or patient room
3. Look for the provider location in the directory
4. Search and confirm insurance coverage
5. Choose demographic information for patient.

While HL7v2 was a step forward in the right direction, the industry has been evolving fast enough where it no longer provides the level of innovation that is needed. There is an increased demand for applications centered around population health, mobile, health, and analytics to be integrated with EHRs. However, these applications need simple, pointed and fast access to data that HL7 v2 can not currently support.