Introduction to Interoperability 101

by Jackie Mulrooney, President, J P Systems, Inc.  

What is meant by the interoperability of clinical data?

Interoperability (IOP) is a multifaceted IT architectural capability which harmoniously orchestrates the exchange of clinical data.  In Healthcare IT (HIT), according to HIMSS: “interoperability is the ability of different information technology systems and software applications to communicate, exchange data, and use the information that has been exchanged. Data exchange schema and standards should permit data to be shared across clinicians, lab[s], hospital[s], pharmacy, and patient[s] regardless of the application or application vendor.”

Interoperability requires organizations (the chorus) with health information systems (the EHR systems being the orchestra) to work together across organizational boundaries in order to exchange clean, properly coded standardized data.  The music produced by the orchestra is the data that flows out and is ‘consumed’ by the audience. Sour notes will send the audience running. Beautiful harmonies will increase those willing to come and hear.

HIMSS defines three increasingly useful levels of health information technology interoperability: Foundational, Structural and Semantic. Foundational interoperability allows data exchange from one information technology system to be received by another but does not require the receiving information technology system to make practical use of the data. This is mere transmission and not of interest here. “Structural” interoperability defines the data structures (format) of data exchange, such as HL7 data messages, where health data is sent in these predefined structures from one system to another so the meaning of the data is unaltered. Once again, this is not the level of interoperability which will protect patient safety. The data must be usable, just because we have sent the data in a nicely organized format does not mean that the receiver is clear on what it all means. These first two levels are akin to pulling a plant up by its roots and tossing it down on top of the soil in another garden without making sure that all the tiny roots will keep on living.  The plant was intricately connected to its soil in its original garden. It must be intricately connected to the soil in its new home.  Otherwise you have dead disconnected data and dead plants. 

True interoperability is the third level called semantic interoperability, where the transplanted data is safely planted in good soil and will bear fruit and be useful where it lands.   Here the roots take and start growing in its new home. The roots get along with the new soil and it stays a useful plant. For this to happen, we need not only standard message data structures but standardized reference data.

What do we mean by standardized reference data?  

You are no doubt familiar with simple look up tables for state abbreviations.  You enter an ‘A” and up comes Alabama, Arkansas etc.. When you pick Alabama, the system then stores not Alabama, but “AL”,  which is the code for Alabama.  Lookup tables in the world of clinical terminologies work in a similar way. A code is stored, not the entire term.  But instead of simple lists, complex terminologies store the terms in hierarchies to show how terms are related to each other.  A state table could have several groups of states for north east, south east, etc.  To find New York, you would first have to first go to the north east group. 

Healthcare IT has various terminology systems overseen by various Standards Development Organizations (SDOs).  The SDOs develop (compose) and periodically release version of their terminologies like a software company releases updates to its software. The various terminologies have various purposes such as classifying known FDA approved drugs (RXNorm), lab tests, lab test results, and listing units of measurement. RX Norm (at NIH NLM) now connects to MED-RT, a VA drug terminology. J P Systems, Inc. led the effort to move the predecessor NDF-RT and merge it into RXNorm.  MED-RT is a terminology used to code clinical drug properties, including mechanism of action, physiologic effect, and therapeutic category. LOINC is an international standard for identifying health measurements, observations, and documents. 

Currently the largest international clinical terminology is called SNOMED, which is overseen by SNOMED International. This is a huge and highly complex hierarchy of clinical concepts sorted first into separate major groups such as body structure, clinical findings, geographic location, or pharmaceutical / biological product.  SNOMED also carefully curates the relationships between the concepts. “SNOMED CT is critical for clinical documentation, as it supports the representation of detailed clinical information in a way that can be processed automatically.” The July 2018 release has 340,659 active concepts. The actual clinical terms are then linked to the concepts. including problem statements, diagnoses.  SNOMED is in use in more than fifty countries. To learn more about SNOMED visit their educational site.

The essence of most issues with IOP is found in the details of the data being exchanged. 

One must ask these questions:

        1) Does my clinical data make full use of codes from standard international terminologies which or are they local codes which mean something only inside
my own organization?

        2) When the data is sent out by my EHR system to external trading partners, is it
being sent as a CDA document? If so, have I looked inside these files (which were
generated automatically)  from the EHR system? Are there data fields which are missing,
misplaced or miscoded?