contact us

HL7 ORU Message – Everything You Need to Know in 2024

Get the inside scoop on the latest healthcare trends and receive sneak peeks at new updates, exclusive content, and helpful tips.

Contact Us

    Posted in HL7

    Last Updated | January 25, 2024

    Executive Summary – HL7 ORU Message

    How do healthcare organizations exchange patient information feasibly? Learn how HL7 standards and HL7 ORU message help share medical data and find out everything you need to know about the ORU message- including its format, contents, and how it can be sent and received in a clinical system.

    Overview – HL7 ORU Message

    Healthcare information exchange is the foundation of concerted efforts to improve care for patients.

    The timely sharing of information among healthcare providers and clinicians helps reinforce better decision-making at the point of care.

    To exchange data, healthcare organizations need communication between their medical devices.

    Since healthcare information is sensitive and vulnerable to hacking, organizations leverage HL7 messages to create a secure mechanism for swapping information.

    Health Level 7 (HL7) messages build on a set of international standards (HL7 standards) that provide a framework for the transmission of clinical and administrative data among diverse medical applications.

    Clinicians, hospitals, and practices use HL7 messages to enable cogs of machines to speak to one another and work as consolidated sources of information.

    Today, more than 90 percent of American institutes use HL7. After its adoption in at least 27 countries, HL7 has become a global standard.

    In line with HL7 standards, HL7 messages aim to provide convenience in the interchange of electronic medical data. Although there are many HL7 messages examples, the ORU message is an overriding method of sharing information.

    In this article, we’ll delve into explaining the HL7 ORU message, its format, contents, and how it can be sent and received, as well as touch on what problems surround its use for information exchange across healthcare.

    What is an HL7 ORU Message?

    HL7 Observation Result (ORU) is an HL7 message used for sharing observational results- including clinical, lab, or other test results- to different systems.

    An HL7 ORU message contains information about a patient’s medical observation. This message is a response generated for the order received from a clinical system. (The order message is called HL7 Order Entry or ORM message).

    ORU message is designed to accommodate information sharing in laboratories, EKG studies, medical interpretations, and imaging studies. It also helps communicate order and results associated with clinical trials (for example, drug development).

    Each ORU message consists of several segments that allow you to construct any clinical report as a multi-level hierarchy and form a complete message.

    HL7 ORU Message Types

    The HL7 ORU message has two different message types.

    1. ORU^R01 HL7 Message

    This message is an unsolicited transfer of information from one system (the result-producing system) to another system (the ordering system).

    This transmission of observation results occurs without receiving an order from the other system. The message helps transmit the results from a producing system (e.g. EKG system, LIS) to a medical record archival system (e.g. HIS, EMR), to register for clinical trials or share medical reporting.

    HL7 ORU R01 message accommodates reporting many types of observations, such as:

    • Imaging study reports
    • EKG pulmonary function study results
    • Lab results
    • Patient condition data or other health data (such as vital signs, allergies, symptoms, notes, etc.)

    2. ORU^W01 HL7 Message

    It is a waveform response or an unsolicited ORU message that transmits requested information (which means the system receives the order and then transfers the data.) This information is waveform data (generated from electrocardiograms) and is the outcome of an ordered series of observations or tests.

    The Structure of an HL7 ORU Message

    ORU message is a hierarchical structure linked with a trigger event. According to HL7, a trigger event is “an event in the real world of health care (that) creates the need for data to flow among systems.”

    Whenever there is a trigger event (such as patient admission or patient discharge), it has an associated abstract message that explains the type of data providers need to share in response to the event.

    The abstract message is a set of segments. The following list illustrates an example of an abstract message associated with a trigger event, A04- Register Patient.

    Trigger events and associated abstract messages

    HL7 integration

    The Contents of an HL7 ORU Message

    HL7 ORU message does not natively contain any images. Instead, the HL7 ORU message format combines codes, texts, and numbers that communicate results.

    An ORU message consists of segments that refer to sections with specific chunks of information that combine to form the overall message.

    In HL7 ORU message, some segments are mandatory, while others are optional ( [ ] indicates optional segments and { } refers to repetition.)

    MSH – Message Heading

    This segment is crucial because it contains information about the receiver and sender and the date and time the message was generated.

    PID – Patient Identification

    Here is when you can include patient-specific information such as name, patient identifier, date of birth, etc.

    Since the message is patient-specific, it must relate to and include information about that particular patient. This segment is mandatory.

    PV1 – Patient Visit

    This section is essential and involves patient visit details such as attending doctor, servicing facility, and visit ID.

    OBR – Observation Request

    It is a crucial segment that helps identify the observation received in OMR to generate an ORU message.

    [{OBX}] – Observation Segment

    This is the segment that holds information about the observation result. An OBX communicates a single observation. For multiple observations, this segment would repeat. It is an optional section and repeats if need be.

    [{CTI}] – Clinical Trial Identification

    CTI is an optional segment and appears if the results link to a clinical trial. It includes information such as the trial ID, the time point, and the study phase. It can occur once or repeat in the same message if there are multiple clinical trial identifications.

    How to Create an HL7 ORU Message?

    You can choose a given template or create your own message. If you pick a message template, here is an example of how you can create a message:

    • From the Profile button (on the HL7 interface), click Generate message
    • Choose ‘HL7 v2. 6 conformance’ from the profile library. Using this profile will generate the ‘HL7 v2. 6 message’.
    • Then, select the ‘ADT-A01’ trigger event. This will create ADT (Admit, Discharge, Transfer) messages.
    • Click ‘OK’

    How to Send an HL7 ORU Message?

    HL7 messages use a variety of TCP/IP protocols for transfer. These include:

    • File Transfer Protocol (FTP)
    • Lower Layer Protocol (LLP)
    • Simple Object Access Protocol (SOAP)
    • Simple Mail Transfer Protocol (SMTP)

    TCP/IP data transmission happens in the form of a stream of bites. So, if there are multiple HL7 messages, you will need to send them as a continuous stream. Although there are many protocols for point-to-point interfaces, the most commonly used method is LLP.

    But, if you have a batch of HL7 processing, you can utilize FTP.


    What is an ORU HL7 message?

    An ORU message is a structured report that contains results of the clinical, lab, and other medical data related to a patient. It facilitates transferring patient information among healthcare providers- switching data from data-producing systems to record management systems.

    Describe the different fields in an HL7 ORU message?

    A single ORU HL7 message spans a collection of segments that create the whole message. Entering data in some of these fields is optional, while others are mandatory and must be filled.

    Here’s a quick view of what these fields are:

    ●     Message Heading – contains sender and receiver’s information and details about the type of message and time and date when it was sent.

    ●     Patient Identification – relates the message to a patient and adds patient data.

    ●     Patient Visit – includes patient visit details

    ●     Observation Results – it identifies the request order to produce the ORU message

    ●     Observation Segment – this segment contains the result of the tests or series of observation

    Discuss common problems with HL7 ORU messages?

    In comparison to older methods of data sharing, HL7 protocols and messages are easier and more efficient at bridging the gap between healthcare systems and facilitating the exchange of data. Although they have many advantages, they also introduce new challenges such as:

    Different Interpretations

    Every system that receives the data can interpret it differently. Additionally, the context and workflows can also influence the semantics. Some systems may use the visit number and others the account number to consider a patient compliant with clinical workflows. Such differences in semantics impact how a system receives and deals with information.

    Optional vs. Required

    Because one chunk of information can be used in several different contexts to achieve different goals, some fields in the message are optional. However, some healthcare products relax or add new data constraint rules to make them mandatory. Therefore, the data shared in messages needs a case-by-case analysis to identify if it’s required or supplementary.

    Customizations in segments and fields

    Field size, data types, and segments are customizable. You need to map the information on a data structure you are acquainted with in order to avoid losing data.

    What is HL7 in healthcare?

    HL7 (or Health Level 7) is a batch of international protocols that ensure the transfer of medical data between different systems correctly and logically. They allow hospitals to communicate and share information whenever they need it.

    For the healthcare domain, HL7 provides application layer protocols with several versions. Its most common version is the 2.x family, and the newest is the HL7 FHIR generation standards framework. FHIR combines the features of Version 2 and Version 3 and has shown immense improvements over these existing standards.

    Because of some similar capabilities, there is confusion surrounding the difference between HL7 vs FHIR. While HL7 is the foundation of these protocols, FHIR builds on it but is a far better and more advanced interoperability standard. FHIR facilitates medical device integration and brings a new level of interoperability to rapidly exchange the growing amount of health data.

    What are HL7 message types ADT ORM ORU?


    ADT stands for Admit, Discharge, and Transfer. ADT messages typically spring from an EHR or registration system. They help keep ancillary systems in sync regarding a patient’s state. As soon as a provider updates a patient’s record, the ADT message is sent.


    HL7 order message (ORM) is an order a clinical system generates to request information or services from another clinical system (such as laboratory data management system.)


    HL7 Observation Result (ORU) is a response to the ORM message. It holds information about a patient’s clinical observations. This message helps transfer the information to the sources that requested the information.

    What is HL7 ORM Message?

    In order and result-based workflows, the HL7 order message (ORM) is used to request a facility or a provider for sharing information.

    Although this ordering method is more common for patient-specific orders, it is also useful for non-patient information requests.

    When it comes to the HL7 ORM message structure, it is similar to the hierarchical structure of the ORU message. HL7 ORM message segments, however, differ from ORU message segments because of the difference in their basic function. The former is the order, while the latter is the response to that order.


    In healthcare organizations, connecting disparate systems to exchange information has always been challenging.

    While interoperability has stepped up to create a seamless connection, the challenges and limitations continue to exist.

    Luckily, with the introduction of HL7 standards for data exchange and defining the format of different message types, healthcare can bridge the gap between multiple settings and seamlessly connect disparate systems to share information.

    HL7 ORU message and OMR message have played a significant role in this regard. They help connect heterogeneous systems to send orders and transfer electronic health data feasibly and securely.

    With healthcare continuing to shift data trends in the future, HL7 messages supported by constant improvements and evolution will be able to maintain their relevance and upgrade to new roles to support new use cases in the long run.

    About the Author

    Noc Folio3