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Anatomy of an EHR: Modules, Interfaces & Workflows

Duration: 45 min · Level: Foundational · Module: 1. The EHR Ecosystem · Focus: modules, workflow, ADT, CPOE, interfaces

Learning objectives

By the end of this lesson you will be able to explain and apply:

  • Core EHR modules
  • HL7 v2 interfaces
  • ADT (Admit-Discharge-Transfer) feed
  • Interface engine
  • CPOE (Computerized Physician Order Entry)

Why this matters​

An EHR system is not a single application — it is an ecosystem of interconnected modules, third-party interfaces, and hardware devices.

Overview​

An EHR system is not a single application — it is an ecosystem of interconnected modules, third-party interfaces, and hardware devices. Understanding how data flows between these components is critical for health information management and for troubleshooting documentation issues.

Key concepts​

Key idea

Core EHR modules: registration/ADT (admit-discharge-transfer), order management (CPOE), clinical documentation, pharmacy, laboratory, radiology, scheduling, billing/claims

  • HL7 v2 interfaces: the old standard that still connects 80% of healthcare systems; ADT messages (A01-admit, A03-discharge, A08-update) trigger record creation across systems
  • ADT (Admit-Discharge-Transfer) feed: the real-time stream that keeps all downstream systems synchronized with who is in the hospital and their current status
  • Interface engine: middleware (Mirth Connect, Rhapsody, Corepoint) that translates messages between systems with different formats; critical infrastructure that most end users never see
  • CPOE (Computerized Physician Order Entry): physicians enter orders directly into EHR eliminating transcription errors; mandatory for Joint Commission accreditation
  • Downtime procedures: every EHR must have paper-based downtime forms and a process for scanning/reconciling records when the system is unavailable; CEHRS exam frequently tests this

Check your understanding​

Try to recall each answer before expanding it.

Q1. What do you know about Core EHR modules?

registration/ADT (admit-discharge-transfer), order management (CPOE), clinical documentation, pharmacy, laboratory, radiology, scheduling, billing/claims

Q2. What do you know about HL7 v2 interfaces?

the old standard that still connects 80% of healthcare systems; ADT messages (A01-admit, A03-discharge, A08-update) trigger record creation across systems

Q3. What do you know about ADT (Admit-Discharge-Transfer) feed?

the real-time stream that keeps all downstream systems synchronized with who is in the hospital and their current status

Q4. What do you know about Interface engine?

middleware (Mirth Connect, Rhapsody, Corepoint) that translates messages between systems with different formats; critical infrastructure that most end users never see

Q5. What do you know about CPOE (Computerized Physician Order Entry)?

physicians enter orders directly into EHR eliminating transcription errors; mandatory for Joint Commission accreditation

← Previous: C1.2 Major EHR Vendors: Epic, Oracle Health, MEDITECH & Beyond · Next: C1.4 The CEHRS Exam Blueprint — Know Before You Study →

Part of Module 1: The EHR Ecosystem.