DEFINITION
De-identification
The process of removing or obscuring identifiers from health data so it no longer identifies an individual, removing it from HIPAA's scope.
In depth
Under HIPAA, de-identified health information is no longer Protected Health Information and can be used or disclosed without restriction. HIPAA recognises two methods: Safe Harbor requires removing 18 specific categories of identifier (names, dates other than year, geographic subdivisions smaller than a state, phone numbers, email addresses, SSNs, medical record numbers, health plan beneficiary numbers, account numbers, certificate and license numbers, URLs, IP addresses, device identifiers, biometric identifiers, full-face photographs, and any other unique identifier) and having no actual knowledge that the remaining information could re-identify an individual. Expert Determination requires a qualified statistician to certify that the risk of re-identification is very small. De-identification is distinct from anonymization (a broader concept without a fixed legal standard) and from pseudonymization (where identifiers are replaced by a code that could be reversed with a key). Properly de-identified data loses HIPAA protection, which is a feature — but the de-identification process itself must be rigorous, since quasi-identifiers (ZIP code + birth date + sex) can re-identify more than 85% of the U.S. population when combined.
Examples
- Removing the 18 HIPAA Safe Harbor identifiers from a patient dataset before sharing it with an AI vendor for clinical research.
- A statistician applying Expert Determination to a health claims dataset to confirm re-identification risk is under 0.05%.
- Replacing patient dates of birth with birth year only and removing all geographic detail below state level before AI analysis.
How Locke handles de-identification
Locke's detection layer is aligned with HIPAA's Safe Harbor identifier list — the 18 categories of identifiers that must be removed for de-identification. By flagging these categories locally before a prompt is sent, Locke helps covered entities apply a de-identification-consistent approach to AI prompts without requiring a formal de-identification workflow for every interaction.
See the productRelated terms
- Anonymization
Irreversibly transforming personal data so that no person can be identified, even with additional information.
- Pseudonymization
Replacing direct identifiers with stable pseudonyms so the data can no longer identify a person without additional information held separately.
- Protected Health Information (PHI)
Individually identifiable health information held or transmitted by a covered entity, regulated under HIPAA in the United States.
