Interoperability in healthcare
The meaning of interoperability is ability of two or more systems (or components) to exchange information and to use the information that has been exchanged. To achieve that goal a set of standards should be implemented to ensure that the information would be properly interpreted by a receiving system in the same sense as was intended by the transmitting system.
There are three main aspects of interoperability:
- Technical interoperability – domain independent aspect concerning moving the data from system A to sytem B, neutralizing the effects of distance. In this transport layer there is no need to know about meaning of what is exchanged.
- Semantic interoperability – specific to domain and context, usualy involves the use of codes and identifiers to ensure that system A and system B understand the set of information without ambiguity. It enables two cooperating systems (or components) to use and interpret the data in the same way.
- Process interoperability – coordination of work processes that enables the business processes at organization that house system A and system B to work together.
The are serveral examples of areas where interoperability of systems plays important role:
- Requests for investigations like laboratory tests or diagnostic imaging
- Prescritpions for medication and other therapy
- Order for patient transport, nursing care, medical equipment
- Different kinds of medical reports (radiology, nuclear medicine, etc.)
- Administrative data: patient registration and identification, clinic reservations, hospital admissions, discharges and transfers
- Medical documents (consultation notes, hospital discharge notes) and any other kind of medical data extracts (electronic medical records)
- Information used for management, audit and monitoring
- Billing, commissioning and accountancy data
The main benefit of developing interoperable systems in the health care field is to provide the right medical information at the right time and place using deployed standards that guarantee safety, security and reliability of data exchange. Information availability is the most crucial issue in medical process.
Health Level 7® organization is responsible for developing standards concerning interoperability in health care domain since 1987. The set of standards known as Version 3 is the most mature attempt to achieve semantic interoperability with its central pillar – Reference Information Model (RIM).
Integrating the Healthcare Enterprise
As far as interoperability standards are concerned there is a strong need to devolop guidelines how to implement these standards to improve the way computer systems in healthcare share information. Integrating the Health Enterprise (IHE) is an international organization that develops open and global Integration Profiles in specific domains.
In each domain users with operational and clinical experience identify the main aspects of integration and information sharing and system vendors develop standard-based solutions to ensure domain-based interoperability. In each domain there is a technical committee resoponsible for documenting this solutions and providing and maintaining technical framework specification. The active domains are listed below:
- Anatomic Pathology
- Eye Care
- IT Infrastructure
- Patient Care Coordination
- Patient Care Devices
- Quality, Research and Public Health
- Radiation Oncology
- Radiology (Mammography, Nuclear Medicine)
Integration Profiles describe specific set of clinical information needed or data workflow and usage of standards to exchange information to accomplish semantic interoperability. The main features of Integration Profiles:
- based on real use cases described by real users
- independend of system vendors and product manufacturer
- stable since published
- extendable by amendments
- implementation guide for system vendors
- effective tool for healthcare providers to describe integration requirements
IHE builds a bridge between healthcare providers requirements, developed standards and systems implementation to ensure interoperability in a specific domains.
Identifiers and code names
Coding systems play very important role in semantic interoperability because of the use of unique idnentifiers for specific medical terms across specialities independend from the data stucture being exchanged. The most valueable are:
- LOINC – Logical Observation Identifiers Names and Codes
- SNOMED CT – Systematized Nomenclature of Medicine – Clinical Terms
LOINC – consists of identifiers for medical terminology related to electronic health records. It is devided into two main parts:
- laboratory LOINC
- clinical LOINC (with subdomain Document Ontology – which covers type of documents and clinical reports).
A unique code format is nnnnn-n. Six fields of the code and their meaning are listed below:
- Component- what is measured, evaluated, or observed (example: urea,…)
- Kind of property – characteristics of what is measured (length, mass, volume)
- Time aspect – interval of time over which the observation was made
- System – context or specimen type (example: blood, urine)
- Type of scale – the scale of measure (quantitative, ordinal, nominal or narrative)
- Type of method – procedure used to make the measurement or observation
SNOMED CT is a systematically organized computer processable set of medical terms providing code names for diseases, findings, procedures, microorganisms, substances, etc. It is designed to store, retrieve and aggregate medical data across specalities and site of care without ambiguity.
The atom of SNOMED is concept – unit uniquely identified by a concept ID characterizing all the things specific for the health care processes that are needed to be recorderd. Concepts are organized into acyclic taxonomic (is-a) hierarchies; for example, Viral pneumonia IS-A Infectious pneumonia IS-A Pneumonia IS-A Lung disease. Concepts are described by several medical clinical terms (called Descriptions). There are three types of them:
- Fully Specified Names
- Preffered Terms
Concepts are linked with each other by connections called relationships.