A Comprehensive Guide to HL7 Messages

hl7 messages

The healthcare industry is incredibly complex and amasses an ever-increasing amount of fragile patient and specialist data. According to insightful studies, each patient has 80 megabytes of EMR and imaging data each year.

In most cases, this data belongs to different medical institutions that process and store it in isolated pools that are poorly structured.

Leading medical institutions utilize various IT systems to manage and operate their diagnostic, treatment, and administrative services. Unfortunately, this hinders effective communication across multiple systems.

HL7 steps in as the ideal solution, useful for transferring electronic data across two or more healthcare systems. Here we’ve created a comprehensive guide to understanding HL7 messages and its benefits:

An Overview of HL7 Messages

Health Level Seven (HL7) is a revolutionary messaging standard that facilitates data transfer across disparate systems. It enhances healthcare interoperability and defines the format for the sharing of healthcare information.

Each HL7 Standard contains the following seven layers:

  • Physical- The first layer is responsible for connecting the physical entity to the transmission information
  • Data Link- Data link controls and reduces any error that may occur within the physical layer
  • Network- It is responsible for conducting data routing for network communication
  • Transport- It maintains communication control within a network
  • Session- Session handles non-communication problems
  • Presentation- It is responsible for converting information
  • Application- It provides the applications an array of services

HL7 standards transmit healthcare data as a collection of messages, with each message sending a single record. Here we’ve added the main types of HL7 standards:

  • HL7 Version 2- The most popular messaging Standard, HL7 Version 2 facilitates the exchange of patient care and clinical information
  • CDA- An ISO-approved standard, CDA relates to the exchange model for clinical documents, including discharge, progress notes, and summaries
  • EHR-PHR Systems- Developers, create EHR systems and their components on system functional models
  • HL7 Version 3- HL7 Version 3 is the enhanced version of HL7V2 and includes messages and documents
  • HL7 EHR- It is an extensive collection of functional models for operating electronic records

Why and How Was HL7 Messages Created

In 1987, Health Level Seven International revolutionized electronic data transmission by introducing Health Level Seven (HL7).

During the 1900s, healthcare organizations started adopting tech to streamline workflow and improve productivity. But these companies opted for several developers for innovating applications for different applications.

Since developers create a new application without collaborating with other application engineering teams, creating custom interfaces meant different languages and communication gaps. Ultimately, it made compatibility impossible.

Health Level Seven International stepped into the market with its team of diligent interface specialists to create a user-led and real-world interface. The introduction of HL7 allowed interoperability and transmission of data across multiple devices.

HL7 includes stringent guidelines that facilitate the sharing and operation of data among various care facilities. The main objective of HL7 was to implement interfaces between healthcare software applications to reduce the cost and pain of custom interfacing.

Today, HL7 is helpful for:

  • Helping healthcare providers connect to offer better patient care
  • Linking doctors with pharmacists to reduce the risks of errors
  • Allowing different hospitals to exchange medical records
  • Connecting laboratories with patient’s health records

Different HL7 Segments

Segments occur only once and ensure a logical and efficient grouping of various data fields. Each segment has a unique name, such as:

  • DG1- Diagnosis
  • FTI- Financial Transaction
  • NK1- Next of Kin or Associated Parties
  • OBR- Observation Request
  • PID- Patient Identification
  • MSH – Message Header: Contains information about the message. It includes the receiver and sender of the message, the date and time of the message sent, and the type of message.
  • PV1 – Patient Visit: Contains information about the patient’s hospital stay, referred physicians, and locations.

Determining HL7 Message Types

Each HL7 message includes a specific message type that explains why you’re sending a particular message.

HL7 messages have specific codes of three characters responsible for triggering an ‘event.’ There are hundreds of message formats, each triggering a different event.

Typically, message events are of the following two forms:

  • Flat Files- HL7 Version 2.4 and earlier use flat files to trigger message events
  • XML- HL7 Version 2.XML and Version 3 utilize XML files to trigger message events

Let’s now discuss the common HL7 message types:

  • ACK- General Acknowledgment
  • BAR- Add or edit billing account
  • MDM- Medical Document Management
  • QRY- Query, Original Form
  • RGV- Pharmacy or Treatment Give
  • SIU- Scheduling Information Unsolicited
  • ADT- Admit, Discharge, Transfer
  • DFT- Detailed Financial Transaction
  • ORM- Order for treatment or pharmacy
  • RDE – Pharmacy/Treatment Encoded Order
  • MFN – Master Files Notification
  • ORU – Observation Result
  • RAS – Pharmacy/Treatment Administration

What are the Components of HL7?

HL7 messages consist of the following components:

1. HL7 Segment

An HL7 message contains one or more segments. It also consists of composites and fields. Each segment contains one specific group of data, such as patient details or patient visit information.

Each segment is separated by a carriage return character (\r), which is a 0D in hexadecimal. Each segment appears on a separate line of text. Furthermore, the name of each segment in the message is mentioned by the first field of the segment and this is always three characters.

One of the common segments found is the message header segment which is detected by the field ‘MSH’. The message header segment includes information about the sender and the receiver, along with the timestamp of the message. Around 120 HL7 segments are available for use in the messages.

2. HL7 Composites

Segments include one or more composites, which are also known as fields. A pipe (|) character separates one composite from the other. Composite is a primitive data type such as a number or a character, or may contain other composites.

If a compositive contains other composites/sub-composites (also known as sub-fields), they are separated by ^ characters. Next, if a sub-composite contains sub-sub-composites then they are separated by & characters. The sub-sub-composites have to be primitive data types.

What are HL7 Delimiter Characters?

Delimiter characters are those special characters that separate one composite in a segment from another one, or separate a sub-composite from the other.

Following is the table of default delimiter characters used in HL7 messages:

Character Purpose
0x0D Signifies end of each segment
| Composite delimiter
^ Sub-composite delimiter
~ Separates repeating fields
& Sub-sub–composite delimiter
\ Escape 

What are Fields?

Fields comprise a string of characters; thus, it is sent as a character string every time you transmit a field. Unless you specify its value, HL7 data fields acquire a null value.

Here’s a glance at the characteristics of a field:

  • Name- It refers to the descriptive name for a specific field
  • Position- The data’s ordinal position or sequence within the field
  • Type of Data- It may vary depending on text data, structure numeric, date, and more.
  • Maximum Length- It refers to the total number of characters a data field can occupy during an occurrence
  • Optionality- It refers to whether your field is optional, required, or conditional
  • Repetition- It determines whether your field will or will not repeat and the number of times a particular field can repeat
  • Table- Valid values for a table may vary depending on the reference, data type, institution, and other data
  • ID Number- It is a small integer value unique to a data field throughout the overall standard

Commonly Used HL7 Message Types

1. ADT

ADT (Admit, Discharge, and Transfer) is the most common and widely used HL7 message types because it offers information for events such as patient registrations, admissions, updates, cancellations, patient data merges, discharges, and much more.

Patient data is fed into the EHR/EMR and updates to these systems are delivered to ancillary systems via ADT messages to maintain syncing of current patient data. There are over 50 different ADT messages which are used for varied patient information.

2. ACK

ACK (General Acknowledgement) type ensures data transmission within healthcare systems. This message is sent as a response to other HL7 message. ACK messages confirm that no data is misunderstood or lost during the communication process between the healthcare systems.

The HL7 message structure of ACK includes a MSH (Message Header) segment followed by ACK. In the MSH segment, the message specifies the sort of message it is acknowledging. The ACK segment includes acknowledgement data such as text message of the acknowledgement and the acknowledgement code.

3. ORM

ORM (Pharmacy or Order for Treatment) is used for transmitting data about orders such as treatments or prescriptions. An ORM message is created when a physician or clinicians place an order within the healthcare system. This could be a request for a diagnostic test or prescription for medication. The message is then transmitted to the concerned department.

4. ORU

ORU (Observation Result) message type is designed to transmit entire data from provider’s system, including lab results and other clinical test results, which are added to patient’s medical record. ORU transfers surplus data efficiently between systems, thus maintaining continuity in care.

5. DFT

DFT (Detailed Financial Transactions) is an integral part of the financial department of the healthcare system. These HL7 messages carry detailed financial information linked to patients’ treatment, diagnosis, insurance, medications, and much more. DFT allows healthcare organizations to manage their financial transactions effectively.

Common Types of HL7 Standards

HL7 provides a robust framework for transmitting, integrating, and retrieving electronic health information. These standards outline the packaging and communication of data across various parties by setting data types, structure, and language.

In addition, HL7 standards improve clinical practices, manage and deliver health services, and ensure seamless integration.

Here we discuss the different types of HL7 standards:

Number 1- Primary Standards

Primary standards are the most common standards necessary for integrating and interoperating systems.

Primary standards comprise the most popular and frequently used standards.

Number 2- Foundational Standards

Foundational standards lay the groundwork for building standards and IT infrastructure used by HL7 implementers.

Number 3- Clinical and Administrative Domains

Clinical and administrative domains encompass messaging and data standards relevant to clinical specialties.

Users typically implement clinical and administrative domains after placing primary standards.

Number 4- HER Profiles

HER profiles refer to the functional models and profiles that help construct efficient systems for the management of electronic health records.

Number 5- Implementation Guides

Implementation guides include all implementation, supporting documents, and insightful guides useful for an existing standard.

Such documents are supplemental data for the pillar parent standard.

Number 6- Rules and References

Rules and references consist of technical specifications, guidelines for software, programming structures, and information about standards development.

Number 7- Education and Awareness

Education and awareness include additional resources that offer detailed HL7 knowledge alongside the documentation of current trial projects.

Understanding the Transmission of HL7 Messages

To send an HL7 message, you’ll have to create a listener so that you can receive it. After this, you’ll have to make a thread that sends HL7 messages.

Once the listener receives your HL7 message, they’ll have to send one back as an ‘acknowledgment.’ Here’s a step-by-step guide to acquiring and acknowledging a message:

Prepare a Console Application

Click on File, New, and Project. Next, select the ‘console’ app and name it something like HL7 Listener.

Make a New Class

Develop a new class and save it as a ‘message’ or something similar.

Create a Segment Class

Next, create another class that comprises information related to the segment. You may name it ‘segment.’

Manipulate Your Segment Class

Integrate methods, fields, and constructors within your class to control it easily. Remember that these fields contain a specific type of message with particular locations.

Why is HL7 Interface Important?

Interoperability helps healthcare facilities communicate while reducing the risks of error. As technology advances and the healthcare industry starts leaning towards software, it’s essential to ensure seamless data integration:

  • HL7 helps healthcare organizations access and retrieve information from other systems
  • It automates workflow and improves interoperability
  • Health Care Seven is critical for storing and exchanging data

Benefits of HL7

Here’s a rundown of the benefits of HL7:

  • HL7 creates a robust electronic record that facilitates communication between healthcare providers and systems
  • Enables accessible communication between multiple systems and the exchange of information securely
  • Helps simplify healthcare processes by offering a standardized data exchange system
  • HL7 facilitates the development of interoperable systems
  • HL7 is a cost-effective solution that helps reduce errors

Let’s discuss its main benefits in-depth:

Boosts Clinical Productivity

Improving correspondence across multiple clinical associations is an excellent way of boosting overall clinical productivity.

With the help of HL7 standards, clinicians can use and share more significant amounts of information. It, in turn, helps improve the productivity and quality of patient care.

HL7 streamlines information exchange which ensures clinicians are always up-to-date with patient data through persistent and easily accessible records.

Ensures Data Uniformity

IT systems often use diverse data formats, functionalities, and transmission protocols. While some legacy techs have built-in data interpreters, others include time-consuming manual inputting features.

By mandating HL7, medical organizations can achieve uniformity and compatibility across multiple data practices. In addition, medical institutions can efficiently collect and process patient information, such as medical billing, admission, and treatment plans.

Eliminates Administrative Errors

HL7 offers clinicians the peace of mind that all data from multiple sources are appropriately synchronized and accessible.

Since they don’t have to fill out data manually, HL7 helps you save time and guarantee accuracy when managing extensive records.

Helps Improve Patient Care

Today’s patients expect medical institutions to provide top-notch quality care alongside easy access to their personal, prescription, and diagnostic data. Thus, the number of digital software and tools is growing across the medical industry.

HL7 provides a uniform framework that aids the intensifying exchange of confidential medical data. Integrating the HL7 interface helps streamline workflow, including acquiring and processing data.

With fewer administrative tasks, medical professionals can concentrate on boosting patient care.

Enables Standardized Data Exchange

Medical institutions often exchange information with other facilities or external healthcare software for research purposes.

HL7 standards effectively bridge the gap in data exchange by integrating web APIs. This revolutionary tool focuses on various data formats like XML and JSON available on mobile applications.

Overall, HL7 allows medical professionals to share and receive data across multiple devices.

Paves the Path for Innovation

HL7 goes beyond providing consistent information transmission between popular frameworks. Instead, it unlocks new opportunities to explore revolutionary software solutions.

It empowers healthcare facilities and other industries to adapt to state-of-the-art and efficient tech solutions.

Provides a Cost-Effective Solution

By adhering to HL7, companies can simplify processes by ensuring a standardized data exchange system. A bonus point of using HL7 is a cost-effective alternative to other similar solutions.

Who Needs HL7 Messages?

You’ll need HL7 if you are:

Clinical Interface Specialists

Clinical interface specialists include individuals tasked with moving confidential clinical information. With the help of HL7, these specialists can move such information and applications safely to different systems.

Clinical interface specialists have to move data between healthcare providers or applicants.

Medical Informaticists

Medical informaticists include people working within the field of healthcare informatics. These individuals create, manage, and operate clinical information.

Thus, using a revolutionary messaging tool helps streamline workflow.

Political Entities

Political entities and governmental bodies often have to share information across multiple devices. Not just this, but these users have to move clinical data in spaces that don’t have current interfaces.

Thus, government healthcare facilities and other political bodies can adapt and mandate a robust messaging standard like HL7.

Healthcare Specialists

Healthcare specialists have to access various systems to check relevant diagnoses and ongoing treatments. It can be challenging, especially in outpatient clinics that are not well-integrated.

HL7 standards and messaging help structure clinical data to effectively reduce the risk of misinterpretation.

Potential Challenges of HL7 Interface

HL7 rarely poses any challenges; however, users have faced the following problems:

  • Acknowledgments won’t generate when you update party information to create disclosures- Since BTAHL7 caches and refreshes every 15 minutes, it’s a wise idea to wait before using it
  • Application Won’t Generate or Receive an ACK- Incorrect information in the MSH3 field restricts the generation and transmission of an ACK, so ensure it’s formatted appropriately
  • Event Errors Appear in the Event Log, and BTAHL7 Can’t Generate an ACK- It may be because a batch in or batch out message contains an empty field. Be sure to format and populate it properly

How is HL7 Interface Unique?

HL7 interface and messaging is the perfect solution for health IT applications. This cost-effective tool makes data sharing more accessible, efficient, and seamless.

Most healthcare providers leverage multiple healthcare applications to manage medical billing, patient information, and other medical-related data. It leads to communication disparities within the healthcare facility and across various providers.

HL7 solves these problems by setting stringent standards to help healthcare providers exchange confidential information.

The Bottom Line

Disregarding innovations is unaffordable in today’s tech-savvy and fast-paced world. Various industries are taking giant leaps to adopt state-of-the-art software to meet the unique needs of the current consumer base.

HL7 acts as a sustainable bridge between advancing IT and modern processes. Industry giants and startups must seize this opportunity to create robust data-exporting environments.