> ## 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.

# Distance

> Base StructureDefinition for Distance Type: A length - a value with a unit that is a physical distance.

## Properties

| Name       | Required | Type                                                   | Description                                     |
| ---------- | -------- | ------------------------------------------------------ | ----------------------------------------------- |
| id         | No       | string                                                 | Unique id for inter-element referencing         |
| extension  | No       | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations   |
| value      | No       | decimal                                                | Numerical value (with implicit precision)       |
| comparator | No       | code                                                   | \< / \<= / >= / > - how to understand the value |
| unit       | No       | string                                                 | Unit representation                             |
| system     | No       | uri                                                    | System that defines coded unit form             |
| code       | No       | code                                                   | Coded form of the unit                          |