Electronic Health Records Fundamentals
What an EHR actually is
An electronic health record (EHR) is a longitudinal, clinician-facing record of a patient's health information that is designed to be shared across care settings. Distinguish it from an EMR (electronic medical record), which is typically a single practice's record, and from a PHR (personal health record), which the patient controls. Questions often test this scope distinction: sharing across organizations points to EHR; patient-maintained points to PHR.
Core functions to know
Be able to name the functions that define meaningful use of an EHR: computerized provider order entry (CPOE), clinical decision support (CDS), e-prescribing, results management, and health information exchange (HIE). Understand the legal health record - the record the organization designates as its official record - versus the designated record set, which is the broader set of records a patient may access and amend. Data elements fall into categories: demographics, progress notes, problems, medications, vital signs, history, immunizations, lab and imaging results.
Interoperability vocabulary
Know HL7 (messaging standards), FHIR (modern API-based exchange), DICOM (imaging), and LOINC and SNOMED CT (terminology). A trap is confusing a messaging standard with a terminology standard. Another trap: assuming an EHR guarantees data quality - garbage in, garbage out still applies.
Worked rule of thumb
When a question asks where a patient's official record lives, ask: who designated it? The legal health record is defined by the organization's policy, not by which system happens to hold the data. If a clinician's personal note is not part of the designated record set, it may not be the legal health record even though it exists in the EHR.
Watch for questions that conflate storage with ownership, or that assume all EHR data is automatically part of the legal record.