> For the complete documentation index, see [llms.txt](https://docs.welkinhealth.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.welkinhealth.com/designer/custom-data-types/custom-data-types.md).

# Custom Data Types

## Overview

Custom Data Types (CDTs) are configurable data structures in Welkin that allow organizations to capture and store structured patient information beyond the default fields. CDTs are the foundation for clinical data collection – from vitals and lab values to custom assessments and medication records.

## What CDTs Enable

With CDTs, your organization can:

* Define custom fields with specific data types (text, number, date, boolean, dropdown, etc.)
* Create repeatable data entries (e.g., multiple blood pressure readings over time)
* Build structured data panels within patient profiles
* Power charts, graphs, and data views based on CDT values
* Trigger automations based on CDT field values
* Export CDT data via API or reporting tools

## CDT Structure

A CDT consists of:

* **Name** – the CDT's identifier (used in conditions and automations)
* **Display Name** – the label shown to care team members in the Care Portal
* **Fields** – the individual data points within the CDT (e.g., systolic, diastolic, recorded date for a blood pressure CDT)
* **Record settings** – whether the CDT stores a single record per patient or multiple records over time

## Common CDT Use Cases

* **Vitals** – height, weight, BMI, blood pressure, heart rate
* **Lab results** – HbA1c, cholesterol, creatinine, with reference ranges
* **Medications** – drug name, dose, frequency, prescriber, start/stop dates
* **Risk scores** – calculated scores from assessments stored as structured data
* **Social determinants** – housing status, food security, transportation access
* **Custom intake data** – any patient attribute not covered by the default data model

## Creating and Managing CDTs

CDTs are created and configured in the CDT Designer within the Welkin Designer portal. For step-by-step instructions, see [CDT Designer](/designer/custom-data-types/custom-data-types-cdt-designer.md).

For field type reference, see [Custom Field Types](/designer/custom-data-types/custom-field-types.md).

***

## Related Topics

* [CDT Designer](/designer/custom-data-types/custom-data-types-cdt-designer.md) – step-by-step CDT configuration
* [CDT Configuration](/designer/custom-data-types/cdt-configuration.md) – advanced CDT settings
* [Custom Field Types](/designer/custom-data-types/custom-field-types.md) – field type reference
* [Create Formulaic CDT Fields](/designer/custom-data-types/create-formulaic-custom-data-type-fields.md) – calculated fields
* [Patient Data View](/designer/programs-and-profiles/patient-data-view.md) – viewing CDT data in Care
* [Data Views](https://docs.welkinhealth.com/care/data-views) – Care-side data visualization


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