What the minimum necessary standard is
The minimum necessary standard sits at 45 CFR 164.502(b), with implementation details at 164.514(d). It tells covered entities and business associates to use, disclose, and request only the PHI a task actually requires. It is a reasonableness standard, not a fixed list of fields, so each organization sets its own policies.
In practice it works at three levels. Staff access is limited by role, so a billing clerk does not see full clinical notes. Routine, recurring disclosures follow standard protocols. Non-routine disclosures and requests are reviewed one at a time against set criteria. Disclosures for treatment between providers are exempt, as are disclosures to the patient.
The standard applies to AI and other software too. A refill outreach list needs a name, phone number, medication, and due date, not the full chart. Sending only the needed columns limits exposure if something goes wrong. Rivvi logs PHI access, which helps an organization show who used which data and when.