> ## 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.

# allergyintolerance_reaction_substance_coding

Normalized `AllergyIntolerance.reaction[].substance.coding[]` property on the [AllergyIntolerance](https://hl7.org/fhir/R4/allergyintolerance.html) FHIR resource.

**Primary Keys:**

* allergyintolerance\_reaction\_substance\_coding\_id

**Foreign Keys:**

* allergyintolerance\_reaction\_id - links to the [allergyintolerance\_reaction](/medical-api/handling-data/schema-v100/allergyintolerance/reaction) table

<div style={{textAlign: 'right'}}><sub>† Metriport Platform added</sub></div>

| Column                                              | Data Type | Description                                          |
| --------------------------------------------------- | --------- | ---------------------------------------------------- |
| allergyintolerance\_reaction\_substance\_coding\_id | varchar   | Unique identifier for the coding row                 |
| allergyintolerance\_reaction\_id                    | varchar   | FK to the parent allergyintolerance\_reaction record |
| code\_rank†                                         | int       | 1-based position of this coding in the source array  |
| code                                                | varchar   | Code value                                           |
| display                                             | varchar   | Human-readable display text                          |
| system                                              | varchar   | Coding system URI                                    |

**Related Tables:**

**Parent:**

* [allergyintolerance\_reaction](/medical-api/handling-data/schema-v100/allergyintolerance/reaction)