MRNs

MRNs, or Medical Record Numbers, are unique identifiers assigned by a healthcare organization to a patient to identify medical records and encounters within that organization. They are not standardized across organizations and may differ between hospitals or clinics.

MRNs are used to retrieve a patient’s chart, orders, results, and billing information within a health system. They help link disparate data to a single patient within that system and typically appear in electronic health records and on patient wristbands. MRNs are not the same as national identifiers such as Social Security numbers or insurance IDs, and they are generally intended for use within a particular institution.

MRNs are created when a patient first interacts with a healthcare provider and remain stable within the owning system. However, MRNs are not inherently portable across organizations; patients seen at different facilities may be assigned different numbers. If a patient is seen in multiple systems, duplicates or mismatches can occur without careful identity management.

Because MRNs are part of a patient’s health information, they are subject to privacy and security protections. Access to MRNs should be restricted to authorized personnel, and disclosure must comply with applicable laws and regulations. Inadequate protection or improper sharing of MRNs can contribute to privacy risks and improper linkage of records.

Interoperability across organizations presents challenges for MRNs. Many systems use a master patient index or patient identity management to reconcile records from different MRNs, but mapping across institutions can be imperfect. Relying on MRNs alone is typically insufficient for reliable patient matching; additional identifiers and demographic data are often used to improve accuracy.

Governance considerations include discussions of national or regional patient identifiers in some regions and the use of tokenized or hashed identifiers to reduce exposure. Policies generally emphasize minimizing identifier sharing, maintaining audit trails, and ensuring appropriate de-identification for research and data exchange.