Electronic medical records (EMR)/electronic health records (EHR) systems were originally developed as stand-alone systems serving one health care organization, such as a hospitals and large private practices. While medical information could be shared easily within a particular organization with EHR / EMR integration, each system captured and stored different elements of a patients health records, and indexed and stored this information using proprietary formats and data schemas. EHR interoperability often involved making copies of records and transmitting them via courier, mail service, or fax.

EHR and EMR vendors have typically viewed proprietary formats as beneficial in terms of locking in customers to their systems, but with increasing EMR integration incentivized by ARRA, EMR interoperability is becoming increasingly critical. While current systems are far from offering complete EHR interoperability and native exchange of medical information, current efforts are focusing on three key elements:

ICD 9 & 10

The International Classification of Diseases, Tenth Revision (ICD-10) was endorsed in 1990 and came into use in World Health Organization (WHO) member states in 1994. Despite the fact it is now almost twenty years old, transition from ICD-9 to ICD-10 is still far from complete. The HIPAA deadline of October 1, 2013 for the transition from ICD-9 to ICD-10 encoding is for hospital treatment inpatient procedures only, and is summarized in this PDF. This change does not directly affect Current Procedural Terms (CPT) coding for outpatient procedures. Despite this exemption for ambulatory care, integrated treatment plans will increasingly require ICD-10 use by most health care providers.

ICD-10 is intended to be inclusive and exhaustive, covering all possible diseases and nature of injury, the external causes of injury, as well as providing a table of drugs and chemicals, and lists of cause-of-death. Whereas ICD-9-CM contains more than 17,000 codes, for example, ICD-10 contains more than 141,000 codes and accommodates a host of new diagnoses and procedures. This drastic increase in diagnostic and procedural codes will present a significant challenge for health care providers.

ICD-10 is specific enough to not only serve as an exhaustive diagnostic and treatment library, but if adhered to properly, to form the basis for a common XML integration of a computer database schema, allowing easier EMR interoperability of data.

Standards implementations often interlock, and the required use of ANSI 5010 as of January 1, 2012 in transmitting claims information is a prerequisite to meeting the ICD-10 claims formatting deadline of October 1, 2013, since the current HIPAA transaction standards cannot support the ICD-10 code formats.


Health Level 7 (HL7) is an American National Standards Institute (ANSI) accredited Standards Developing Organizations (SDO) operating in the healthcare arena. Health Level Seven produces standards for health care clinical and administrative data. The name of the organization is a reference to Level 7 of the Open Systems Interconnection (OSI) model, which is the Application Layer. The original process for defining HL7 messages was established in 1987.

HL7 has created Messaging Standards, as well as standards for Continuity of Care Documents (CCD), and Clinical Document Architecture (CDA) files. These standards describe how lab results are reported, immunization registry data is exchanged, public health events are reported, and legacy EHRs exchange clinical summary data with each other.

While a useful and widespread standard, HL7 interoperability is limited in capability, and essentially serves as only a simple messaging standard.


This is the standard for transmitting prescription information using a simple file structure similar to HL7. The scope of this messaging standard is limited to providing data interchange for pharmacy services.

Give the need for a simple means of communicating securely and easily with the more than 50,000 pharmacies in the United States, and the highly limited and standardized information that must be transmitted, NCPDP standards are expected to remain in widespread use.