If you are unfamiliar with HL7, then you are in the right place. Let’s learn all that there is to know about this virtual interface used in the healthcare industry. HL7 helps meet the unique needs of healthcare organizations, such as data sharing and integrated care management. The introduction of HL7 in healthcare has streamlined the workflow and supported new technologies.  

So, what does the HL7 interface mean?

HL7 stands for Health Level-7, which is an international set of standards that establishes a network for sharing electronic health records (EHRs) between software platforms in the healthcare sector. HL7 standards are de facto standards in healthcare IT. HL7 was created by Health Level Seven International, which is a non-profit organization that strives to provide a comprehensive framework and standards supporting the sharing and retrieval of electronic data. It is used by many large institutions in over 55 countries, which agreed upon a standard format for all types of patient data exchange. HL7 was accredited by the American National Standards Institute (ANSI) in 1994 to govern the healthcare system stakeholders and vendors’ standards developed. Health level 7 standards supply formats and frameworks for promoting data exchange in clinical settings. 

There are four main HL7 standards: HL7 version 2, version 3, CDA, EHR-PHR, and FHIR

Four versions of HL7
  • HL7 Version 2 (V2) is the most commonly used messaging standard for the exchange of electronic health records. It is a database query language that helps healthcare providers to send messages asking for and storing patient data.
  • HL7 version 3 (V3) is also emerging and it varies significantly from V2.
  • CDA (Clinical Document Architecture) is an ISO-approved standard that creates an exchange model for clinical documents such as discharge summaries and progress notes. CDA is associated with continuity of Care Documents (CCD) and Consolidated Clinical Data Architecture (C-CDA). CCD consists of a record of patient discharge and admission in different facilities. On the other hand, C-CDA is applicable in certified EHRs for consolidating CDA templates into a single document.
  • The EHR-PHR System Functional Models supply standard language parameters used for creating EHR systems and their components.
  • Fast Health Interoperability Resources (FHIR) is a Web-based data exchange language that speeds interoperable healthcare applications and makes them simpler and easier.

More details about HL7 FHIR

  • FHIR, which stands for Fast Healthcare Interoperability Resource, is pronounced as “fire”.
  • Unlike the HL7 standards, the FHIR standard was established for the web.
  • FHIR is an upcoming and still-developing method of integration.
  • HL7 FHIR brings together the topmost characteristics of HL7 versions like HL7 V2, HL7 V3, and CDA
  • FHIR is created based on modular components known as resources that can be combined to overcome clinical and administrative challenges. It is possible to extend the resources for promoting adaptation to develop manageable solutions for optionality and customization.
  • Healthcare systems can easily interpret the extensions by employing a similar framework to other resources.

What are the differences between HL7 V2 and V3?

HL7 V3 addresses certain problems that are inherent in HL7 V2, which also gives rise to some new challenges. Let’s see the benefits and challenges posed by each of these versions.

Difference between HL7 V2 and V3

Some key features

HL7 represents the seven-layer International Standards Organization (ISO) Communications Model:

  • It connects the entity to online transmission media
  • Provides error control between adjacent nodes
  • Moves data across a network 
  • Provides communication control for the end-users
  • Tackles other problems apart from communication issues
  • Converts data into a form that users can interpret
  • Offers a variety of services to the applications

Why was HL7 developed in the first place?

Past challenges: In the past, data interchange across different healthcare systems took place through customized interfacing systems. These interfaces required extensive programming at the sending and receiving applications, which complicated the process. The difficulty with interfaces arises when healthcare teams and software vendors develop new applications. Each application is created without input or collaboration with other application systems.

The Innovation of HL7: Some clinical interface specialists in the healthcare industry decided to invent a better and more cost-effective approach for interface applications. A few acute care hospitals and software vendors came together as a volunteer group to innovate a standard way of building interfaces. Their goal was to reduce the price of building interfaces substantially. This is how HL7 came into existence.

The objective of HL7: 

Objective of HL7

The main purpose of creating HL7 was to simplify the implementation of interfaces involved between healthcare software applications and various vendors. Doing so would decrease the cumbersomeness and expenditure towards custom interface programming that would support compatible applications. The focus was on making it adaptable to allow simpler data exchange and significantly reduce costs. Implementing HL7 resolved 80% of the clinical interfacing problem flexibly.

An Example of HL7 Integration

HL7 Integration

A healthcare communications company utilized HL7 integration to obtain inputs from various hospital systems. The data included the EHR, patient care devices, laboratory, radiology, nurse call systems, and much more. This information was communicated to the healthcare teams through various mobile devices, such as smartphones and tablets.

What is the role of HL7 in the healthcare sector?

Healthcare professionals often need to access multiple electronic data systems to correctly diagnose patients. This process can become more difficult if providers offer services in outpatient clinics separate from the local hospital system. FHIR HL7 interoperability standards, including HL V2, make things easier for clinicians. These standards provide a common language for handling and sharing patient data across EHRs without risk of misinterpretation or duplication.

What are the Benefits of HL7 implementation?

Besides helping you optimize EHR systems and make them cost-effective, HL7 offers many advantages:

  • Creates a single, flexible, worldwide standard for the movement of clinical data.
  • Allows easy sharing of complex and private patient data, including records, lab reports, test results, etc., through clinical applications.
  • Smoothens the process of electronic data interchange so that the end-uses can interpret the data.
  • Makes integrated healthcare solutions possible, thus improving the care services delivered by healthcare networks.
  • HL7 standards are healthcare-specific formatted messages that support different healthcare system integrations and interoperability.
  • These standards allow EHRs to communicate with many systems operating outside the EHR.

About HL7 Message Structure

About HL7 Message Structure

Health Level 7 message structure is a standardized format used in the health industry to exchange healthcare-related information between different applications and systems. HL7 messages are designed to be interoperable and flexible, allowing seamless data sharing. Here’s an overview of the HL7 message structure:

1. Segments

The HL7 message structure consists of one or more segments, and each segment contains specific categories of information. Segments are known as the basic building blocks of the HL7 message. Each segment starts with a three-letter string that detects the segment types and ends with a carriage return. A segment may contain several fields.

2. Fields

Segments contain fields that are separated by pipe characters (“|”). Fields can have assigned value types and each field has a specific purpose, like admission date or patient name.

3. Components

Special delimiter characters, such as caret (“^”), are used to further break and split fields. These data elements provide more particular information. For example, a caretaker’s name field might be divided into components for first, middle, and last names.

4. Sub-components 

If components contain composites, then these are sub-components and are the smallest data units. These sub-components are separated by an ampersand (“&”). It is used for further specification within a component. It must be primitive data types.

What Are the Different HL7 Message Types?

What Are the Different HL7 Message Types

There are different types of HL7 messages, each serving specific purposes within the healthcare domain. Here’s an explanation of some common HL7 types:

1. ADT (Admit, Discharge, Transfer)

The purpose of ADT messages is to provide patient demographic and administrative information related to admissions, discharges, and transfers within a healthcare facility. When a patient is admitted, an ADT message is generated, providing information like patient ID, patient room number, and attending doctor. The common segments used are PID (Patient Identification), PV1 (Patient Visit), PV2 (Patient Visit – Additional Information), DG1 (Diagnosis), etc. 

2. ORM (Order Entry)

ORM messages are used to request services or procedures (orders) for patients. It transmits information about orders for tests, procedures, or medications. This message type is fundamental in radiology, pharmacy, and laboratory systems. It provides details like the order date, the item ordered, and the ordering physician. The common segments used are OBR (Observation Request), ORC (Common Order), OBX (Observation/Result), etc. 

3. MDM (Medical Document Management)

MDM messages are used for medical document management like transmitting clinical documents, reports, and notes. These are typically used by Radiology departments to communicate provider transcriptions, order information, and document contents. The commonly used segments are MSH (Message Header), EVN (Event Type), PID (Patient Identification), etc.

How can HL7 help with EHR/EMR interoperability?

EMR/EHR Interoperability

Modern healthcare technology aims at healthcare automation and data sharing at different point sources. One of the major concerns in allowing the secure and smooth sharing of electronic health records is avoiding interoperability issues. Electronic medical record (EMR) or electronic health record interoperability will reduce medical errors, improve clinical performance, and enhance patient access to healthcare. Data interoperability is a crucial component for communicating health data. There are two ways of transferring health data across platforms: legacy and web approaches. 

Legacy approach:

  • Legacy systems require agreed-upon file formats for recording health data, so that everyone knows what goes where. The files can be used and reported.
  • Legacy systems have to depend on compiling different data into a single text file and transmitting it securely. HL7 is the primary standard for these files.
  • HL7 has established Messaging Standards and standards for Continuity of Care Documents (CCD) and Clinical Document Architecture (CDA) files. 
  • The various HL7 standards explain structured data put together into a text file.
  • HL7 also interprets reporting of lab results, data exchange, and more.

Web approach:

  • Web applications are designed for sharing it widely.
  • Web-based IT is emerging, and it is used for communicating data. Keys are needed to protect data privacy.
  • Web applications do not require legacy methods, including HL7.

Now that you know the importance of HL7 in emerging healthcare applications, let’s take a look at some of the problems that may arise while integrating HL7.

FHIR vs. HL7 V2: Which Is Needed For Healthcare Interoperability

Today, every other individual has smartphones and access to the internet. Healthcare IT leaders needed to revamp the framework of healthcare information exchange to ensure the new developments. Even Grahame Grieve, product director of FHIR at HL7, thinks that healthcare information exchange needs to be seen from a contemporary context. 

As HL7 V2 was created way before the internet outbreak, it’s obvious that the standards won’t be that relevant today. HL7 V3 still tried to address certain challenges that HL7 V2 couldn’t. However, the main problem with the implementation of HL7 V3 was its complexity. So, healthcare leaders and facilities felt the need for a better version of HL7.

FHIR in HL7 was formed to accommodate web-based service technologies, smartphones, and other emerging technologies. Fast Healthcare Interoperability Resources, as per HL7 standards, has made data exchange faster than ever. Since FHIR, healthcare interoperability has also significantly developed, especially after the HITECH Act of 2009.

Moreover, the pandemic revealed health information exchange issues, and interoperability has become a critical investment. With healthcare organizations and decision-makers actively working to adopt interoperability, FHIR HL7 in healthcare is the much better version to ensure secured information exchange; no matter how many apps or digital touchpoints are used. 

HL7 Integration Benefits

With large amounts of healthcare data generated daily, the exchange of data storage in isolated pools is poor. Health institutions suffer due to their disorientation. Imagine a hospital using HIS, LIS, EMR, RIS, and PACS; all these systems generate data in different formats that can hinder effective communication. Only HL7 integration can ensure standardization and resolve this issue. Here are some of the significant benefits of integrating HL7 in healthcare.

1. Data Uniformity: Healthcare facilities might use different legacy IT systems created by software developers. These systems use different data formats and transmission protocols. While some of these systems already have in-built data interpreters, others sometimes lack this functionality. And transferring data becomes a time-consuming, manual job. However, integrating HL7 interfaces can resolve to take care of this issue. It’s because adherence to HL7 standards enables health institutions to achieve complete compatibility for their data exchange practices.   

2. Rapid Decision-Making: Rapid decision-making can save lives in a clinical setting. Physicians need to make quick yet informed decisions, especially in emergency situations. And for that, critical information related to patients’ health needs to be at physicians’ disposal. Through HL7 integration, hindrances due to inconsistency in data formats and other information exchange issues are resolved. And physicians can make much faster decisions. 

3.  Improved Patient Care: Today’s patients actively maintain their health and expect a certain range of services. Patients increasingly use online methods to access their personal diagnostic data alongside digital health apps and wearables, so they need a reliable way to ensure secure data exchange. HL7 provides a safe and secure ecosystem for medical data exchange.  

4. Standardized Data Exchang: Information sharing internally is much easier. But often, there’s a need to share information across external health institutions for clinical research or referral reasons. HL7 data integration ensures seamless interoperability through FHIR and web-based APIs. This new standard focuses on data formats like XML and JSON, primarily supported by mobile applications. That means HL7 makes data sharing with external sources easy and seamless.

HL7 Integration Use Cases  

With the benefits of HL7, it’s obvious that HL7’s uses in the healthcare industry are quite varied. Today, care providers leverage HL7 integration in a wide spectrum of cases. Take a look at these cases-

1. Information Sharing with Regulators: The healthcare industry is heavily dependent on regulations. Facilities and providers must share information with regulatory authorities. Achieving Health Level 7 compliance can facilitate and simplify this process.

2. New Patients’ EHR Management: As HL7 integration assures seamless interoperability, it can benefit hospitals with the EHR data of new patients coming to the facility. Integration of HL7 ensures that the data from the EHR system of another hospital is shared seamlessly with the other facility, saving providers time and money.    

3. Seamless Information Exchange between Hospitals: One of the major benefits of the HL7 standard highlighted earlier is the seamless exchange of information between hospitals. HL7 data integration enables this uninterrupted information flow to improve hospital communication. Moreover, FHIR and web-based APIs make it easier for facilities to share patient health information with other practices and expand the knowledge base.    

4. Shift Management: It’s quite clear that today’s staff are overwhelmed with the workload. However, with HL7 integration, healthcare organizations can feed their shift management system with the required data and oversee real-time feedback. This will help them align the needs of clinical staff with care demands, and staff will also not feel burdened. HL7 makes it easier for providers to match the caregivers’ preferences and abilities with patients’ loads to ensure fair and effective shift allotments.     

5. Improved Patient Services: Patients want to be equally involved in their care process. Just like how they manage their work or finances, patients expect the same from their healthcare providers. They want every piece of information about their health at their fingertips, so digital apps and remote care are becoming popular. They need access to sensitive information, and providers must ensure secure data protocols. Integrating HL7 can take care of these and improve patient services drastically.    

6. Automation of Process: Process automation saves healthcare providers time and money. And HL7 standardized data workflows make it possible. It enables the staff to avoid manual data entry processes and information sharing between departments. All data from care episode records, lab test results, prescriptions, and more can be synchronized and structured using HL7 integration. 

Does HL7 integration come with challenges?

HL7 may seem simple, but HL7 is associated with many challenges for software vendors and healthcare organizations. The flexibility due to HL7 enabling different environments to use different versions and aspects of HL7 can also make interfacing between unrelated systems very difficult. Here’s a list of challenges that you may come across while integrating HL7 into your healthcare system:

HL7 Challenges

Integration is vital for application viability: 

  • Any application, no matter how essential it is, will require the extra effort of Clinicians and Healthcare experts. They will need to be convinced to use it, and a simple just won’t work.
  • It is not easy for clinicians to stop using a certain EHR platform and login to an unrelated system and duplicate the existing data. This integration and asking healthcare experts to use a new tool may not be practical.
  • As it is, healthcare professionals have tight schedules. For HL7 to be viable, the applications must have a closed-loop integration, with data being extracted from the electronic health records and stored in it.
  • This problem can be overcome by hiring HL7 integration experts. They will help you make the applications readily accessible to clinicians, eliminating data duplication.

Integration may consume time and resources due to HL7: 

  • You may observe a significant variance in the application of HL7 standards, which slows cycles, and integration becomes a time-consuming and expensive process. As a result, it requires resources for developing and simplifying integration.
  • If interfaces are added or replaced, each application interfacing with the updated version is affected, which can impact the functioning of the whole system.
  • Adequate implementation of HL7 can be facilitated by changing each endpoint for the updated app.
  • Additionally, all software vendors having interfaces linked to the app should also replace or alter their endpoints. You need experts to successfully implement HL7 interfaces that will allow seamless communication between the interfaces.

Likelihood of data misinterpretations caused by poor HL7 semantics: 

  • If data is misinterpreted, it can create problems, especially in the healthcare industry.
  • Applications must understand data values and interpret them correctly.
  • HL7 interfaces should clearly communicate the interpretation of the standard used to prevent data misinterpretation. For instance, does a value of NA mean No Allergies or Not Applicable?
  • If misinterpreted, such data can hamper the quality of the entire dataset and have severe implications on patient care delivery.

Transforming to a new EHR may lead to loss of legacy data: 

  • While moving data for migration, it is important to prioritize the data.
  • You need to choose what you would like to keep and what to discard.
  • It may not be feasible to convert certain data, and errors may be produced during migration via HL7.
  • HL7 integration may result in unexpected expenses and consume a lot of time.

How to overcome the issues with HL7?

Overcoming issues with HL7

Here’s how to overcome the issues with HL7:

  • Interface engines are commonly used as an HL7 integration solution, but they have their downfall. Interface engines require PHI to be stored in a second database, which can result in risks to data security.
  • One of the most effective ways of dealing with HL7 challenges is utilizing healthcare APIs. EHR integration with API allows electronic data exchange without lowering PHI security.
  • Standardizing data integration via real-time APIs and a standard model will assist you in managing the problems. API successfully manages the HL7 interface, so it avoids the waiting period and fastens the HL7 implementation process. Software vendors and healthcare professionals need to agree on an API solution that will resolve HL7 integration issues and eliminate EHR interoperability.
  • Planning strategies for dealing with HL7 problems, along with coordinated testing, can allow the successful implementation of HL7 interfaces. Such interfaces can decrease the chances of duplicated data entry and enhance the workflow of end-users.

What Are the Best Practices in HL7 Integration?

What Are the Best Practices in HL7 Integration

1. Point-to-point Interfaces

The point-to-point interface method establishes direct interfaces between individual systems using HL7 messaging. Through customized interfaces, every system is connected to a counterpart system. Let’s understand it with an example, a hospital can implement a direct HL7 interface between its EHR system and laboratory information systems (LIS). Whenever any physician orders test results through electronic health records, the order gets transmitted directly to the LIS using HL7 messages. Then the lab results are sent back to the EMR through the same interface. You may find this method simple to implement but it increases the number of interfaces that are hard to handle.

2. Middleware and Integration Engines

The next common approach for HL7 interface integration is through the HL7 integration engine. It is a type of middleware that can manage HL7 messaging between multiple systems. This middleware acts as a centralized hub for managing HL7 messaging and data sharing among EHRs, radiology systems, etc. The integration engine can transform data formats according to the standards of different systems and can also coordinate the message workflow. Also, it is important to consider the UX design as it can optimize the integration engine’s functionality. A proper UX design eases the message workflow and data communication.

3. HL7 Integration Services

Some health organizations use HL7 integration solutions or services to connect their existing systems with those of other healthcare organizations. There are only a few service options available in the market, but it is always advised to conduct thorough research to determine the best fit for your needs.

4. Health Information Exchange

The entities participating in the health information exchange (HIE) frequently use HL7 messaging protocols to share healthcare data. HIE exchanges healthcare data among different organizations and systems within a geographic community or region. It allows health professionals and patients to access and share patients’ medical histories electronically and securely.

What is the future of HL7?

The future of FHIR HL7 is shaped by ongoing developments in healthcare technology, interoperability needs, and advancing standards. Here’s what the future looks like:

  • HL7 standards were introduced to allow the integration of advanced tools to transfer critical information with. 
  • HL7 integration is expected to increase the efficiency of each healthcare sector and reduce the scope for errors. 
  • HL7 certainly will continue to support technological advancements such as integrated healthcare. However, healthcare providers must ensure that HL7 standards are HIPAA Compliant.
  • HIPAA compliance will improve, and healthcare centers will have a streamlined workflow as per the new EHR guidelines.
  • HL7 will be recognized as an essential component of healthcare integration.
  • Development of applications supporting both versions of HL7: V2 and V3.
  • HL7 standards adapting cloud-based healthcare IT architectures.
  • HL7 will be more approachable and simpler to engage with.

HL7 Certification and Training

The growing demand for the HL7 integration process raises the jobs associated with it. Hence, it is better to hire HL7-certified professionals. With HL7 certification, the professionals achieve industry-recognized levels of expertise and proficiency in HL7 implementation and development. It increases career opportunities and helps you stand out from the crowd by becoming HL7 certified.

HL7 offers certification and proficiency tests that assess the knowledge and proficiency of its most frequently used health information technology (HIT) standards. Hence, HL7-certified professionals gain the confidence of the employer and increase the chances of you being hired.

Do you need assistance with HL7 implementation?

We, at OSP Labs, have experts who can resolve challenges related to HL7 development. These are some of the HL7 services we can help you with:

  • Configuration, monitoring, and HL7 integration support
  • DICOM image connectivity, security, and storage solutions
  • Streamlining workflow using HL7
  • Solutions for technical issues
  • And much more


The healthcare industry is evolving with the development of the HL7 standards because they enhance integrated healthcare applications’ usability. Health level 7 or HL7 stimulates data interoperability, thus promoting data sharing between different health professionals. Healthcare informatics requires HL7 to ensure cost-effectiveness and efficacy. The incorporation of healthcare APIs assist the smooth functioning of applications operating through HL7. There are different types of HL7 standards, among which, V2 is more popularly used. However, systems supporting both versions V2 and V3 may develop. Although HL7 has its many benefits and crucial applications, it does come with challenges. With appropriate planning and strategies in place, it is possible to develop relevant solutions for the problems.

Key takeaways

  • HL7 stands for Health Level-7.
  • It is a standard developed by an international organization for sharing patient information between software platforms in the healthcare sector.
  • There are different kinds of HL7 standards. V2 is commonly used, and HL7 FHIR is associated with web-based applications.
  • HL7 interface supports EHR integration and allows easy migration of data.
  • Healthcare APIs avoid waiting periods and speed up the HL7 implementation process.
  • HL7 has its set of challenges, but with adequate planning and resources, they can be resolved.



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