Integrating with Epic using HL7 V2

For digital health innovators looking to connect their solutions with major electronic health record (EHR) systems, Epic HL7 V2 integration remains one of the most important pathways. While newer standards such as FHIR are increasingly being adopted, HL7 Version 2 (HL7 V2) continues to underpin a vast range of clinical and administrative workflows in Epic, thanks to its flexibility, maturity, and wide industry acceptance. Understanding how Epic uses HL7 V2 is critical for innovators aiming to ensure their products can exchange data seamlessly with Epic environments across the globe.

The Role of HL7 V2 in Epic

HL7 V2, first introduced in the late 1980s, is a widely implemented standard for healthcare data exchange. Despite being decades old, it continues to dominate integrations in large healthcare ecosystems, especially with established EHRs such as Epic. HL7 V2 messages are compact, relatively easy to parse, and capable of handling the breadth of healthcare workflows that modern systems require. Epic leverages HL7 V2 extensively through its Bridges platform, which acts as the central hub for message routing, processing, acknowledgements, and error handling. This allows healthcare organisations to connect Epic with external systems such as laboratories, pharmacies, registries, imaging systems, billing applications, and medical devices, while maintaining real‑time or near‑real‑time data synchronisation.

For innovators, HL7 V2 offers a proven and reliable integration pathway into Epic, ensuring that digital health tools can access or supply the clinical, operational, and financial data needed to enhance patient care and organisational efficiency.

Key Categories of Epic HL7 V2 Interfaces

Epic provides a large portfolio of HL7 V2 interfaces, each designed to support specific use cases. Rather than offering a one‑size‑fits‑all feed, Epic structures its HL7 V2 ecosystem into incoming and outgoing interfaces, each tailored to a defined workflow. Understanding the categories of these interfaces is essential for any digital health innovator considering Epic HL7 V2 integration.

One of the most common categories is clinical data exchange, where external systems provide or consume information such as laboratory results, radiology reports, pathology updates, and even discrete genomic results. Epic’s HL7 V2 interfaces support both results reporting and order communication, enabling third‑party laboratory systems or imaging providers to work seamlessly with Epic’s native modules such as Beaker, Radiant, and Cupid. For example, an innovator building a novel diagnostic platform could use Epic’s Incoming Ancillary Results interface to deliver test results directly into the Epic EHR, while the Outgoing Ancillary Orders interface could allow Epic to send test orders to that platform.

Equally important are medication and pharmacy workflows, which are deeply integrated into Epic through HL7 V2. Interfaces such as the Outgoing Verified Medication Orders from Willow Inpatient allow Epic to transmit pharmacy orders to automated dispensing systems, while the Incoming Fill Status Updates interface ensures Epic knows when a prescription has been filled, cancelled, or dispensed. Innovators working in medication adherence, robotic dispensing, or digital pharmacy management can use these interfaces to create a tight loop between their solutions and Epic.

Administrative workflows are also heavily supported via HL7 V2. These include patient administration (ADT) interfaces, which handle demographic updates, insurance coverage, bed status changes, and admissions, discharges, and transfers. Scheduling interfaces, such as Incoming Appointment Scheduling and Outgoing Appointment Scheduling, allow innovators to integrate scheduling tools or patient engagement platforms with Epic, ensuring clinicians and patients always have an accurate view of upcoming appointments.

Financial integration is another important area where HL7 V2 continues to play a role. Interfaces such as Incoming Financial Transactions and Outgoing Financial Transactions enable Epic to work alongside third‑party billing or claim‑scrubbing systems, which can be particularly relevant in markets where organisations use external revenue cycle management solutions.

Finally, Epic HL7 V2 is essential for public health and regulatory reporting. Interfaces exist for vaccination registries, syndromic surveillance, electronic laboratory reporting, and cancer reporting through NAACCR standards. Digital health companies focusing on population health analytics, epidemiology, or immunisation programmes can use these interfaces to streamline compliance with local and national reporting requirements.

How Epic HL7 V2 Integration Works

From a technical perspective, Epic HL7 V2 integration is handled through its Bridges module. Bridges is responsible for sending, receiving, and processing HL7 V2 messages. Each HL7 V2 message is composed of segments and fields that define the type of data being exchanged, such as patient demographics, orders, results, or financial transactions. Bridges ensures that these messages are properly formatted, delivered, and acknowledged.

There are two broad categories of HL7 V2 interfaces in Epic: incoming and outgoing. An incoming interface brings data from an external system into Epic. For example, a remote laboratory sending results to Epic would use an Incoming Ancillary Results interface. Conversely, an outgoing interface transmits data from Epic to an external system. For instance, an Outgoing Imaging Results and Orders interface allows Epic to send radiology orders and results to an external PACS or transcription system.

Most interfaces are configured as TCP/IP connections using the Minimal Lower Layer Protocol (MLLP), a well‑established transport method for HL7 V2. Messages are usually processed synchronously or asynchronously, depending on the use case. Epic also supports asynchronous acknowledgements, ensuring that message delivery and processing can be tracked reliably across complex workflows.

For innovators, one of the most important aspects of Epic HL7 V2 integration is interface configuration. Each organisation using Epic may tailor their HL7 V2 interfaces to meet their specific needs, which means that innovators must plan for a degree of customisation during implementation. Although Epic provides standard specifications, there is often variation in how data elements are populated or interpreted, requiring careful mapping, testing, and validation.

Opportunities for Digital Health Innovators

The scope of Epic HL7 V2 integration presents significant opportunities for digital health innovators. By connecting via HL7 V2, innovators can ensure their solutions are embedded in the clinical workflow, providing value where it matters most: at the point of care. For example, a company specialising in remote patient monitoring could use Incoming Device Data interfaces to feed vital signs from wearable devices into Epic, where clinicians can validate and review the data. Similarly, innovators developing AI‑driven diagnostic tools could integrate their results into Epic using HL7 V2, ensuring that clinicians see these insights alongside other patient information.

Another opportunity lies in streamlining care coordination. Using interfaces such as Incoming External Encounters or 360X Closed Loop Referrals, innovators can support continuity of care across different organisations and care settings, helping to reduce duplication and improve patient outcomes. Meanwhile, innovators focusing on patient engagement can benefit from HL7 V2 appointment and patient administration interfaces, enabling real‑time synchronisation of patient schedules, demographics, and communication preferences.

Financial technology providers in healthcare can also find value in Epic HL7 V2 integration. By connecting with Epic’s billing interfaces, fintech innovators can introduce automation, fraud detection, or real‑time analytics into the revenue cycle without requiring healthcare organisations to abandon their existing Epic systems.

Challenges to Consider

While the opportunities are extensive, digital health innovators should also be aware of the challenges associated with Epic HL7 V2 integration. HL7 V2, though widely adopted, is a complex standard with many optional fields and local variations. This means that even when using the same Epic specification, two organisations may configure their interfaces differently. Ensuring interoperability often requires extensive mapping, testing, and ongoing support.

Moreover, HL7 V2 interfaces are transactional and context‑driven. Unlike FHIR, which is more API‑like and supports granular queries, HL7 V2 messages are often event‑triggered. For example, a lab result message is only sent when a result is finalised, and an ADT message is generated when a patient is admitted or discharged. Innovators must design their systems to handle these event‑based updates effectively.

Regulatory compliance is another important consideration. Interfaces dealing with sensitive patient data must adhere to data protection regulations, such as the UK GDPR, and ensure secure transmission, storage, and access control. Epic provides robust infrastructure to support this, but innovators must also ensure their systems are equally compliant.

Finally, Epic HL7 V2 integration often requires close collaboration with the healthcare organisation implementing Epic. Since interfaces must be configured within Bridges, external innovators cannot connect independently; they must work with Epic customers and, in many cases, with Epic themselves to enable and test the necessary feeds.

The Future of Epic HL7 V2 Integration

Although FHIR is increasingly seen as the future of healthcare interoperability, HL7 V2 is unlikely to disappear any time soon. Its entrenched position, breadth of coverage, and reliability mean that Epic HL7 V2 integration will remain essential for many years to come. For digital health innovators, investing in HL7 V2 capabilities is therefore not only a way to ensure compatibility with Epic today but also a foundation for long‑term interoperability as organisations gradually adopt FHIR alongside existing HL7 V2 feeds.

Innovators who master HL7 V2 integration with Epic position themselves strongly in the healthcare technology ecosystem. By understanding the categories of available interfaces, navigating the technical and operational complexities, and designing solutions that work seamlessly within Epic’s Bridges infrastructure, they can deliver meaningful value to healthcare providers and, ultimately, to patients.