Semantic Interoperability for Electronic Health Records

Whenever I lecture about standards harmonization, I'm asked how far along we are on the journey toward interoperability. First a definition of interoperability:

Technical interoperability - the ability to send a human readable record from place to place. A fax machine, secure email, and sending of free text from EHR to a PHR are examples of technical interoperability. For example, at present, Microsoft Health Vault enables documents and photos to be sent from a hospital, clinic, lab or pharmacy to a secure personal health record. Once there, they are viewable by the patient. However, at present, Microsoft Health Vault cannot combine multiple documents together to create a single uniform medication list, problem list and allergy list for the patient. Health Vault supports technical interoperability but not semantic interoperability.

Semantic interoperability - the ability to send human readable and computable records from place to place. An electronic health record with vocabulary controlled, structured problem lists, medications, labs, and radiology studies sending this data into structured lists within a personal health record is an example of semantic interoperability. Semantic interoperability ensures that decision support software can interpret the transmitted data and perform quality and safety checks such as drug/drug or drug/allergy checking. Google Health supports semantic interoperability for problems, medications, allergies and laboratories. The Continuity of Care Document, the clinical summary which has been recognized by Secretary Leavitt and the American Health Information Community (AHIC) is semantically interoperable, as detailed below.

Process interoperability - Per my recent blog about Decision Support Service Providers, wouldn't it be great if the best practices for healthcare including protocols, guidelines, care plans, and rules were transferable from one organization to another? Sending a clinical summary from one organization to another would immediately result in event driven medicine based on all the new data provided. Unfortunately, we really have not achieved this degree of interoperability.

At this point in the standards harmonization work, based on the efforts of 500 organizations working in HITSP over the past 2 years, we have achieved semantic interoperability for Electronic Health Records and Personal Health Records using the Continuity of Care Document clinical summary Here's the state of the art of interoperability:

a. Problems - CCD contains human readable and semantically interoperable problem lists, using SNOMED CT as the problem list vocabulary.
b. Medications -CCD contains human readable and semantically interoperable medication lists, using RxNorm as the medication list vocabulary.
c. Allergies - CCD contains human readable and semantically interoperable allergy lists, using UNII as the vocabulary for Food and Substance allergies and RxNorm for Medications.
d. Notes - CCD contains human readable structured and unstructured clinical notes/reports. Additional HL7 ballots over the next few months will provide even more options for structured notes via the Clinical Document Architecture.
e. Labs - CCD contains human readable and semantically interoperable lab results using LOINC vocabularies to describe the lab test and UCUM to indicate the unit of measure of the result.
f. Radiology - CCD contains human readable reports, but does not yet include images. In 2008, the HITSP Consultation and Transfer of Care use case will require us to develop interoperability specifications to share images.
g. Vital signs - CCD contains human readable and semantically interoperable vital sign measurements, using LOINC as the vocabulary to describe the site and method of measurement for each vital sign.

Thus, in 2008, we have all the standards needed to send structured information from provider to provider, from provider to patient, and from provider to public health agency. Of course, this data must be sent with appropriate security to protect the privacy of the patient. My blog entry tomorrow will describe the national, regional and local efforts that ensure confidentiality is maintained per the wishes of the patient.