> ## Documentation Index
> Fetch the complete documentation index at: https://docs.metriport.com/llms.txt
> Use this file to discover all available pages before exploring further.

# patient_identifier

An identifier for this patient, such as MRN or SSN (`Patient.identifier[]`).

**Primary Keys:**

* patient\_identifier\_id

**Foreign Keys:**

* patient\_id - links to the [patient](/medical-api/handling-data/schema-v100/patient/base) table

| Column | Data Type | Description |
| - | - | - |
| patient\_identifier\_id | varchar | Unique identifier for the identifier row |
| patient\_id | varchar | Parent patient |
| system | varchar | Namespace/URI that defines the identifier value |
| value | varchar | The identifier value |
| use | varchar | Intended use of the identifier (e.g., official, usual, temp) |
| type\_text | varchar | Human-readable type description |
| period\_start | datetime | Start of the period when the identifier was valid |
| period\_end | datetime | End of the period when the identifier was valid |

**Related Tables:**

**Parent:**

* [patient](/medical-api/handling-data/schema-v100/patient/base)

**Child:**

* [patient\_identifier\_type\_coding](/medical-api/handling-data/schema-v100/patient/identifier_type_coding)


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.