LINKMED® Interface Tutorial: HL7 Basic

1.0 What is HL7?

Health Level Seven is one of several ANSI-accredited Standards Developing Organizations (SDOs) operating in the healthcare arena. Most SDOs produce standards (sometimes called specifications or protocols) for a particular healthcare domain such as pharmacy, medical devices, imaging or insurance (claims processing) transactions. Health Level Seven’s domain is clinical and administrative data. Their mission is to: "To provide standards for the exchange, management and integration of data that support clinical patient care and the management, delivery and evaluation of healthcare services. Specifically, to create flexible, cost effective approaches, standards, guidelines, methodologies, and related services for interoperability between healthcare information systems."

Important Notice: The following HL7 tutorial required LINKMED® IE software.

1.1 HL7 Interface Overview

In health care, a trigger event is a real-world event that creates a need for data to flow among systems. A trigger event, for example, can be admitting, transferring, or discharging a patient. This document demonstrates how triggered events can be put into message format and delivered to other vendor systems.

This web page tutorial has message formats that consist of data fields that are of variable length and separated by a field separator character. Rules describe how the various data types are encoded within a field and when an individual field may be repeated. The data fields are combined into logical groupings called segments. Each segment begins with a three-character literal value that identifies it within a message. Segments may be defined as required or optional and may be permitted to repeat. Individual data fields are found in the message by their position within their associated segments.

2.0 Message Transactions

A message is a unit of data transferred between systems. It is comprised of a group of segments in a defined sequence. Each message has a message type that defines its purpose. For example, the ADT (Admission, Discharge and Transfer) message type is used to transmit portions of a patient's ADT data from one system to another. The three-character code contained within each message identifies its type (ADT, ORM, ORU).

Example of HL7 ADT Message:


Example of HL7 ORDER (ORM) Message:


Example of HL7 Unsolicited Result (ORU) Message :


Example of HL7 Medical Documentation Management (MDM) Message:


Example of HL7 Billing (DFT-Detail Finacial Transaction) Message:


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