The term interoperability refers to the ability of health information technology concepts to send and receive information in a manner that preserves its accuracy, context and completeness. For example, if two different EHR systems contain data on the same patient and they are able to exchange data in a manner that allows both systems to treat the imported data as if it had been entered by a local user, the systems are deemed to be interoperable. At this time there are over 600 proprietary EHR systems and virtually none of them are truly interoperable with each other.
The reasons for this are tied to a lack of implemented standards that would allow two disparate systems to speak the same “language,” when it comes to sharing health care data. For example, there are over 400 proprietary codes used by over 400 EHR systems that all mean “admitted to hospital.” Until one common code is used by all systems, there will continue to be challenges associated with each system’s ability to send and receive information to and from other systems.
Some progress has been made over the past 20 years with the development of standards that would allow health care systems to communication with each other.
- A group called Health Level 7 (HL7) developed a vehicle for sharing data called the Clinical Document Architecture (CDA). The CDA is a basic standard for creating electronic documents that can be exchanged between health information technology systems such as Electronic Health Records (EHRs) and Health Information Exchanges (HIEs). CDA takes advantage of the HL7 Reference Information Model (HL7 RIM) and features a predetermined set of data types, specific vocabularies (e.g., RxNorm, SNOMED CT, LOINC, etc.). It is in Extensible Markup Language (XML) format that allows for the specific attribution of concepts.
- A group called ASTM developed a tool called the Continuity of Care Record (CCR). CCR is a standardized data set that defines what terminologies can be used for messages between healthcare systems. From the perspective of the CDA, it have value in that it can be used to constrain CDA specifically for summary documents (e.g., for single or multiple episodes of patient care).
- These two approaches were combined around 2007 to create a something called the Continuity of Care Document (CCD). The CCD is meant to be an vehicle that any EHR can send and receive. It contains areas where codes that represent medical terms and the actual medical terms can stored. The ability to create and send a CCR and/or a CCD file is one of the requirements for EHRs to be certified for the Meaningful Use of EHRs.
- The HL7 Consolidated CDA (C-CDA) is being used to further specify how information is shared in the 2014 Edition Certification Program for Health Information Technology (Stage 2 Meaningful Use, 2014 Edition). The C-CDA includes HL7 CDA templates for specific concepts such as clinical visits or discharge summaries. Commonly used templates were harmonized into a single “implementation guide.” Stage 2 Meaningful Use guidance includes includes criteria for:
- Transitions of care (Transition of Care/Referral Summary)
- Data Portability (Export Summaries)
- View/Download/Transmit (Ambulatory or Inpatient Summary)
- Clinical Summary (Clinical Summary)
In summary, Stage 2 Meaningful Use criteria mandate the use of a consolidated group of CDA templates (colletively referred to as C-CDA). This has the potential to markedly increase data interoperability, including the use of standard vocabulary sets like SNOMED CT and LOINC. It will be a significant step toward healthcare information portability and giving access to patient information in real-time.
Additional Suggested Reading: Companion Guide to the CCDA for MU2
The information contained in this article represents the opinions of its author: Michael Stearns, MD
©Michael Stearns, all rights reserved