HL7 Messages Examples: Decoding HL7 Message Structures

Posted in HL7

The secure exchange of patient information is important in the healthcare industry. It improves patient care and ensures compliance with legal standards, ultimately leading to positive health outcomes. HL7 messages are the standardized language used for data exchange in healthcare setups to ensure secure and efficient transfer. They provide a structured interoperability format, incorporating security measures to protect sensitive information. These messages are structured into segments that convey information about specific events like admissions, discharges, and test results. Let’s take a closer look at HL7 messages examples.

What are HL7 Message Examples?

HL7 message types, whether HL7 ADT (Admit, Discharge, Transfer) messages or others, all follow a structured format comprising segments that act as building blocks, containing specific data points using standardized codes. The HL7 data format ensures clear communication regardless of the encoding characters or the HL7 file format used. 

By understanding these components, we can decipher the intricate language of HL7 messages (ADT and others) and unlock the power of data exchange across healthcare networks.

HL7 message examples are used whenever healthcare data needs to be transferred between different systems or multiple healthcare providers. An HL7 message is a hierarchical structure that acts as a message envelope connected to a trigger event, such as when a patient is being admitted into a clinic or when they are being discharged. A collection of one or more messages is used to send information using the standard HL7 data format, each transmitting one record or piece of health-related information.

What is the HL7 Message Structure?

A sample of HL7 messages can clearly depict one or more parts of their structure, making up different lines of text. Every HL7 message contains the HL7 message types, indicating its function or purpose.

A carriage return character (\r) separates each segment from the next, further containing fields, segregated by the pipe ‘|’ character. On the other hand, every field may contain sub-fields, separated by the ‘^’ character.

HL7 data types define the kinds of information that can be stored within an HL7 message structure fields; common examples include:

• Strings
• Text
• Timestamps
• Addresses
• Coded elements

These data types ensure consistency and standardization in how healthcare systems represent and exchange information.

Each HL7 message includes a message type dictated by a three-character code, indicating why the message is being sent and the corresponding triggered event. The MSH-9 field of the message contains both the message type and the trigger event. 

Understanding an HL7 Message Example 

In an HL7 message, for example ADT-A01:

• The field ADT is the HL7 message type
• A01 is the trigger event

This type of message reads as a “patient admit” message.

How Many Types of HL7 Messages Are There?

There are many types of HL7 messages, each with its own unique purpose and message content. Each message has a specific code of three characters, serving to trigger an event. 

While there are numerous messaging formats in HL7, the most common include ACK (General Acknowledgment), ADT: Admission, Discharge, and Transfer, which carry patient demographic information, and ORM: Pharmacy/Treatment Order Message which carries information about an order. The ORU message type: The observation message type transmits observations and results, such as clinical lab results and imaging reports, from the producing system. SIU: Schedule Information message type creates, modifies, and deletes patient appointments and has 14 different trigger events.

Similarly, clinics use the RDE: Pharmacy/treatment Encoded Order Message to send orders to pharmacies. Other important messaging types in HL7 include BAR—Add/change billing account, QRY—Query, original mode, MFN—Master files notification, and DFT—Detailed financial transaction.

Most Common HL7 Message Types

Some of the examples from the HL7 message types list include: 

• ACK – General acknowledgment
• ADT – Admit, Discharge, Transfer
• BAR – Add/change billing account
• DFT – Detailed financial transaction
• MDM – Medical document management
• MFN – Master files notification
• ORM – Order (Pharmacy/treatment)
• ORU – Observation result (unsolicited)
• QRY – Query, original mode
• RAS – Pharmacy/treatment administration
• RDE – Pharmacy/treatment encoded order
• RGV – Pharmacy/treatment give
• SIU – Scheduling information unsolicited

What is an HL7 ORU Message?

HL7 Observation Result (ORU) is an HL7 message used to share patient observational results, including clinical, lab, or other test reports, between different systems. An HL7 ORU message contains information about a patient’s medical observation. It is a response generated for the order received from a clinical system. (The order message is called an HL7 Order Entry or ORM message.)

An HL7 ORU message is designed to transmit patient observational results, such as clinical and laboratory data, between healthcare systems in response to orders from clinical systems. They support various structures, such as laboratory results, EKG studies, and clinical trials. The format allows detailed reporting through multiple segments, ensuring accurate communication of health information.

HL7 ORU Message Types

There are two types of HL7 ORU messages:

1. ORU^R01: This unsolicited message transfers information from the result-producing system to the ordering system without a prior request. It conveys various observations, including imaging study reports, lab results, and patient condition data.
2. ORU^W01: This waveform response transmits requested information after receiving an order, primarily focusing on electrocardiogram data.

The Structure of an HL7 ORU Message

An ORU message has a hierarchical structure linked to a trigger event, an occurrence that necessitates data transfer among systems. Each message comprises multiple segments like MSH, PID OBR, etc., separated by carriage returns (\r), with fields within segments divided by pipes (|) and sub-fields by carets (^).

Components
of HL7 ORU Message

What Does ADT in HL7 Message Types Stand For?

ADT stands for notifications of admission, discharge, and transfer. These are frequently cited as crucial components of enhancing patient care coordination through health information exchange.

When a patient is admitted, transferred, or discharged from a hospital, ADT HL7 messages are sent to notify people associated with the event. These messages help inform doctors and their teams about a patient’s status for proper follow-up and communication. This highly benefits patients who battle multiple or chronic diseases.

ADT HL7 message also assists in identifying frequent users of the healthcare system. It enables medical professionals to direct them patients toward clinical and non-clinical therapies, lowering overutilization of resources and unnecessary ER trips and hospital readmissions.

This HL7 message example, ADT, improves healthcare communication by conveying both patient personal data and information about trigger events. These events include:

• Patient admissions
• Discharge
• Transfers
• Registrations 
• Cancellations
• Patient updates

Due to its ability to handle multiple trigger events, HL7 ADT messages are highly valuable and often account for the highest volume of messages exchanged.

Segments in HL7 ADT

An HL7 ADT message is composed of several segments, each displayed on a different line of text containing a particular category of information. 

The main segments in an ADT message include:

• MSH (Message Header): This header identifies the type of message, sending and receiving applications, and other details about the message.
• EVN (Event Type): Contains information about the event that triggered the message.
• PID (Patient Identification): Provides demographic information about the patient.
• PV1 (Patient Visit): This form contains information about the patient’s visit, including the facility’s location and the attending physician.

HL7 ADT Message Types

There are different HL7 ADT message types, each representing a particular event in a patient’s healthcare journey. Some of the common ADT HL7 message types include:

• A01—Admit/Visit Notification: This message is sent when a patient is admitted to the facility. It includes key data points like patient demographics, admission date, and assigned ward or department.
• A02 – Transfer a Patient: An A02 message is generated when a patient is transferred from one location to another within the facility. It contains details of the patient’s new location and the transfer time.
• A03 – Discharge/End Visit: This message is sent when a patient is discharged from the facility. It includes the discharge date and time, along with any final diagnoses.
• A04 – Register a Patient: An A04 message is used when a patient is registered at the facility but not admitted. It includes patient demographics and registration details.
• A08—Update Patient Information: This message is sent when the patient’s demographic information changes. It contains updated information, like a new address or contact number.

Each ADT message type serves a unique purpose and contains specific data points relevant to the event it represents. Understanding these types can help healthcare professionals effectively manage patient information and coordinate care.

What Does ORM Stand For in HL7?

“HL7 ORM” refers to the Order Entry message type within the HL7 framework. It initiates the transfer of order information and contains actions like placing new orders (lab tests, radiology, medications, etc.) and canceling existing ones. The most prevalent ORM message is ORM-001, which supports the transmission of order details and significantly impacts healthcare communication by ensuring a seamless information flow.

The HL7 ORM message acts as a request for services or materials, linking multiple healthcare providers through order details. Whether utilized in laboratory or radiology departments, these messages structure order processing, ultimately enhancing patient care and outcomes.

What Are the Types of ORM Messages (orm^001)?

The ORM, or Order Entry message in HL7, is a universal format used in healthcare systems to share order-related information. The HL7 ORM message format is a structured language that enables communication between different health services.

There’s only one type of ORM message, ORM^001 or ORM-O01, and its responsibility is transmitting details about an order. It includes actions like placing new orders, canceling existing ones, and more.

The HL7 ORM message structure consists of one or more segments, each displayed on a different line of text. This structure allows for the clear and efficient transfer of information within the healthcare system. An ORM^001 message improves healthcare communication by providing an efficient and standardized method for sharing order-related data.  

What Are the Contents of an HL7 ORM Message?

An HL7 ORM message consists of several segments, each having a specific purpose and collectively forming a comprehensive order message. The exact composition varies based on the details of the message, and optional or custom segments may be included in certain implementations. 

Below are the most common segments found in an HL7 ORM message:

MSH (Message Header): The first segment in every HL7 message, the MSH identifies the sending and receiving applications, the date and time of the message, the message type (ORM), and the HL7 version, establishing the context for the entire message.

PID (Patient Identification): This segment carries essential patient information, including patient ID, name, date of birth, sex, and address, and helps in patient identification within the HL7 message.

PD1 (Patient Additional Demographic): The PD1 segment provides additional demographic details about the patient, such as preferred language, living arrangements, and publicity code, enriching the patient’s profile.

PV1 (Patient Visit): Related to patient visits, this segment contains important fields like admission type, assigned patient location, and attending physician, offering context about the patient’s current or most recent visit.

ORC (Common Order): Central to the ORM message, this segment holds order-related information such as order control code, order status, and transaction date/time, outlining the specifics of the order.

OBR (Observation Request): This segment specifies the requested tests and includes fields like test name, specimen source, and observation date/time. It is crucial to detail what tests or observations are being ordered.

DG1 (Diagnosis): The DG1 segment contains information about the patient’s diagnosis, including diagnosis code, type, and date, providing valuable insights into the patient’s health condition.

How to Read Sample HL7 Messages and HL7 Files?

Here is what a typical HL7 message looks like:

MSH|^~\&|ADT1|MCM|FINGER|MCM|198808181126|SECURITY|ADT^A01|MSG00001|P|2.3.1

EVN|A01|198808181123

PID|1||PATID1234^5^M11^ADT1^MR^MCM~123456789^^^USSSA^SS||

SMITH^WILLIAM^A^III||19610615|M||C|1200 N ELM STREET^^JERUSALEM^TN^99999?

1020|GL|(999)999?1212|(999)999?3333||S||PATID12345001^2^M10^ADT1^AN^A|

123456789|987654^NC

NK1|1|SMITH^OREGANO^K|WI^WIFE||||NK^NEXT OF KIN

PV1|1|I|2000^2012^01||||004777^CASTRO^FRANK^J.|||SUR||||ADM|A0

Before reading this complicated HL7 message, you should understand its various parts. Each HL7 message contains segments, fields, components, and subcomponents. Every line in a message is called a segment and contains information of a specific type. Each segment has a three-character label, such as ‘MSH,’ ‘PV1’, ‘NK1’ or ‘PID,’ and a hierarchy of fields and sub-fields grouping related data. 

The ‘|’ character separates various fields within each segment. If a segment or field is repeated, it is indicated by the presence of the ‘~’ character. Within each field, components are separated by the ‘^’ character, while sub-components are separated by the ‘&’ character.

Now that you can sort out every part of the message, it is time to decipher each segment separately. Remember that each message segment contains one specific category of information, evident from the three-character code. 

In our example message, we see at least four different HL7 segments. The MSH segment holds information about the sender and receiver of the message, as well as the time stamp. Since this segment contains vital information, every HL7 message has MSH as the first segment on top and EVN (event type) as the second segment. 

The PID segment contains patient demographics, such as name, medical ID, location, etc. The Next of Kin (NK1) segment delineates information about the patient’s next of kin, while the PV1 segment includes every piece of data related to the patient’s hospital stay, such as the doctor and assigned room. Each segment ends with “0x0D.”

Each segment consists of several fields, separated by ‘|.’ Each field can be a primitive data type or contain more fields (sub-fields), denoted by the character ‘^’ with further sub-sub-fields, separated by the ‘&’ character.

Remember that segments are either mandatory or optional. For instance, the MSH (Message Header Segment) and PID (Patient identification) segments are necessary to understand messages such as ADT^A04 (Register Patient). Other segments, such as those containing patient allergen information, are optional since patients may or may not have allergies.

Discover How Folio3 Digital Health Delivers Tailored Solutions With The Power Of HL7 To Improve Workflow Efficiency and Secure Data Transfer.

3 Interesting Facts About HL7

With the digital wave, the healthcare system is continuously changing, and with more HL7 implementation, different types of HL7 messages are used.

Standardized Healthcare Lingo

HL7 messages are a common language for healthcare data, ensuring consistent communication between disparate systems. An HL7 ADT (Admit, Discharge, Transfer) contains specific HL7 segments that transmit patient information using standardized codes, regardless of the HL7 file format or encoding characters used. This consistency helps prevent misunderstandings when exchanging HL7 messages (ADT or other message types) and improves patient care.

Seven Layers of Structure

HL7 isn’t a single standard but a suite of standards organized into seven distinct layers. Each layer tackles a specific aspect of data exchange, like how HL7 messages are formatted (including segments) or how security is handled in an HL7 file. This layered approach allows for much flexibility and customization, regardless of the message structure or file format.

Global Reach, Local Impact

HL7 is a global standard used in healthcare systems. While the core principles of HL7 encoding and message types remain the same, specific regional variations may exist in its implementation. This can affect how HL7 ADT messages or other message types are structured or used in different healthcare settings.

Explore how Folio3 Digital Health Empowered Igenomix To Securely Share Patient Information Across Various Platforms with HL7 Integration.

How Are Hl7 Messages Transmitted?

HL7 messages are generally transmitted using the TCP/IP protocol over a local network, such as within a hospital. TCP/IP data is sent as a stream of bytes, which means that numerous messages may be sent as a continuous stream. However, this creates confusion since we need to define a starting and ending point for each HL7 message. 

This is where you can use the Minimal Lower-Layer Protocol to add a header and footer to each message to mark its beginning and end. These headers and footers are not actually shown in the transmitted message.

HL7 message transmission requires an adequately designed protocol in the hospital. A well-structured UX design in healthcare will help ensure proper protocol implementation and, hence, proper HL7 message transmission. You can also depend on Folio3’s integration service for a good UX design.

Folio3 hl7 integration solutions work accurately alongside some of the most challenging healthcare apps.

What is HL7 V3?

Health Level 7 Version 3 differs from Version 2 since it supports exchanging clinical information and electronic documents in XML syntax. The V3 specification was released to eliminate variances and improve interoperability between all standard users. Another difference is that v3 includes messages and documents, also called clinical document architecture.

HL7 Delimeter Characters

How Can You Tell If A Message Is An HL7 V2?

A typical HL7 V2 message has a 3-character string identifier, such as ACK (Acknowledgement), ADT (Send Demographic Update), or RSP (Return Immunization History). The trigger of a V2 message is a real-life event that necessitated communication, such as patient admission into a clinical facility. 

Unlike flat file structures, version 2 messages can be expanded or shortened to carry only the necessary data. For instance, some segments and fields are optional or repeated. If no information is available for a patient’s next of kin (NK1), this segment can be removed, or if there are multiple Next of Kin, each would have a separate NK1 repeat segment. 

Each V2 message comprises several segments, each with its own identifier and a separate line. Every segment consists of composites, which carry the data, and the ‘|’ character separates each field within a segment. A ‘^’ character separates each sub-composite within a field while the ‘~’ character precedes the repeating fields.

This is what a simple V2 ACK message looks like!

MSH|^~\&|Main_HIS|XYZ_HOSPITAL|iFW|ABC_Lab|20160915003015||ACK|9B38584D|P|2.6.1|
MSA|AA|9B38584D|Everything was okay dokay!|

Here, the MSH segment contains information about the message, such as the time stamp and the sender and receiver, with the MSH-10 field containing the message ID. 

When a message is acknowledged, this field includes the same identifier as the message it acknowledges. The second segment, MSA, denotes its status; here, the status is AA, which translates to Positive acknowledgment. The ID of the original message is returned to the MSA.

How To Read an HL7 File?

You need software such as Health Level 7 to open and read an HL7 file. Windows won’t be able to open it without proper software, resulting in an error. 

If you cannot open your HL7 file correctly, click “Open with” and choose the pertinent application.

Can You Define HL7 DFT?

The DFT message defines a financial transaction utilized for patient accounting and communicated to a billing system. This message is delivered between the DSS/Order Filler and the Charge Processor and may contain information such as ancillary costs or patient deposits. The DSS/Order Filler would check to see if the process was finished.

The following are examples of DFT-P03 message triggers:

• Ordered a procedure
• Scheduled procedure
• Performed the procedure

HL7 Message & Uses

Seamlessly Integrate EMR Solutions Powered By HL7 With Folio3 Digital Health 

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Conclusion 

HL7 messages examples are a vital part of secure data exchange in the healthcare industry. They provide a standard framework for communicating and transmitting information between different systems. HL7 relieves administrative burdens, improving overall healthcare.

Frequently Asked Questions

What is MSH HL7?

The MSH segment contains important information about the message itself, such as intent, source, and destination, as well as some specifics of its syntax. It includes both the message type and trigger event.

What Is An A08 message of HL7?

ADT-A08 (update patient information) messages notify the receiving systems of a change in a patient’s address or name.

What Is an A04 HL7 Message?

ADT-A04 message relates to the “register a patient” event. This alerts that a patient has arrived or checked in as a one-time or recurring outpatient with no bed assigned. This message is sent to both emergency room patients and outpatients. 

For instance, HL7 A04 could signify the start of a trip to the emergency room (also known as casualty, etc.). Some systems may use the term “outpatient registrations” or “emergency admissions” to describe these occurrences. The visit start date and hour are specified in PV1-44—Admit Date/Time.

What Are the Different Ways to Integrate Cerner with HL7?

• Direct integration: This involves connecting Cerner directly to the HL7 server. This is the most secure method of integration, but it can be complex and expensive to set up.
• Web services: This involves using web services to exchange data between Cerner and the HL7 server. It is more scalable and cost-effective than direct integration but less secure.
• File-based integration: This involves exchanging data between Cerner and the HL7 server in files. It is the simplest and least expensive integration method but less secure than the other methods.

Are Any Specific HL7 Messaging Standards or Versions Used in Allscripts EHR Integration?

Allscripts EHR integration supports HL7 v2.x messaging standards, which are widely used for interoperability in healthcare. However, it is essential to note that Allscripts may have specific implementation guidelines or customizations based on their product versions, so it’s advisable to consult Allscripts documentation or support for particular details related to their integration capabilities.

What Is An HL7 Segment?

Think of HL7 segments as logical groupings of data fields. Each HL7 message consists of several segments characterized by a unique 3-character code identifier. Each segment contains one specific category of information, such as patient visit data or insurance data. About 120 segment codes are available for HL7, including MSH, PID, NK1, and PV1.

Is HL7 a Programming Language?

HL7 is not a programming language; rather, it is a set of international standards for data uniform exchange in healthcare. It defines message formats and protocols.

What Is The Sample Structure of the HL7 Message?

In its most basic form, each HL7 message consists of segments, fields, components, and sub-components. Components and subcomponents further contain the data within data fields.

What Are The Various Types of HL7 ADT Messages?

There are 51 types of ADT messages, but a few common ADT messages include:

• ADT-A01 – patient admit.
• ADT-A02 – patient transfer.
• ADT-A03 – patient discharge.
• ADT-A04 – patient registration.
• ADT-A05 – patient pre-admission.
• ADT-A08 – patient information update.
• ADT-A11 – cancel patient admission.
• ADT-A12 – cancel patient transfer.

What Types of Data Can Be Exchanged Using HL7 Messaging in Healthcare Integration?

HL7 messaging supports the exchange of various types of healthcare data in healthcare integration, including:

• Patient demographics: Name, age, gender, address, contact information, etc.
• Clinical observations: Vital signs, laboratory results, imaging reports, medication administration records, etc.
• Orders and referrals: Diagnostic orders, medication orders, appointment requests, referrals to specialists, etc.
• Administrative information: Admission/discharge/transfer (ADT) data, insurance details, billing codes, etc.

What Is The Z Segment in HL7?

A Z-segment is a message segment that contains clinical or patient data but isn’t part of the HL7 standard. The option to add Z segments makes HL7 such a flexible standard, with all its segments starting with the “Z.”

What Is An HL7 ORM Message?

In HL7, the ORM is a general order message used to transmit information about an order. It has only one type: the ORM-O01 message.

What Does OBX Mean in HL7?

The OBX segment transmits key clinical observations/results back to the requesting system, to another physician system, or to an archival medical record system.

What HL7 Message Has Medicines Listed?

The HL7 RDE message places orders to medication dispensing systems and may contain a full list of the medications a patient has been prescribed.

How Do You Convert The HL7 Message into XML?

The easiest way to convert raw HL7 messages to XML is to use a HL7 to XML Transformer.

What is PV1 in HL7?

The patient visit segment (PV1) contains basic inpatient or outpatient encounter information. Registration/Patient Administration applications most commonly use this type of message to communicate information on an account—or visit-specific basis.

Is HL7 a Type of File?

Most HL7 format files come from Health Level Seven. In the healthcare industry, computerized medical and administrative information is exchanged, retrieved, and integrated using the HL7 data interchange format.

What Is The Field for Compendium in HL7?

The Laboratory Test Compendium Framework within HL7 delineates the laboratory order codes for systems that support the electronic laboratory ordering functionality. Folio3’s team of HL7 integration experts offers exceptional Folio3 EHR/EMR integration services to help organizations gain seamless HL7 integration solutions.

What Types of Data Are Covered by HL7 Encoding Requirements for State Health Departments?

HL7 encoding requirements for State Health Departments typically cover a broad range of health-related data, including:

• Patient demographics and identifiers
• Laboratory results
• Vital signs and observations
• Immunization records
• Reportable diseases and conditions
• Syndromic surveillance data
• Public health reporting information

Why is HL7 Messaging Important in Medical Device Integration?

HL7 messaging plays a crucial role in medical device integration as it provides a standardized way for medical devices to communicate with healthcare systems. By using HL7 messages, medical devices can transmit data in a format that is easily understood and interpreted by receiving systems, facilitating the integration of device data into electronic health records and other clinical applications.

Is DFT an HL7 Message Format?

Financial data is transmitted using the HL7 Detailed Financial Transaction (DFT) protocol between different systems and to a billing system. It is used for patient accounting and claims creation and includes details on patient billing and accounts receivable, billing accounts, charges, payments, adjustments, and insurance.

The Department System Scheduler (DSS)/Order Filler (i.e., the service provider) and the Charge Processor are the parties involved in a typical HL7 DFT message transmission (i.e., insurer or payee). When the DSS/Order Filler confirms that the patient has received the requested service, the Charge Processor obtains the necessary patient demographics and account information for patient registration.

What is The Difference Between ORM and ORU Messages?

HL7 ORM vs ORU is simple. ORM messages are used to place orders for tests or procedures, while HL7 ORU messages are used to send results back to the ordering system.

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