---
layout: default
title: Mapping Tables
nav_order: 2
parent: Code Terminology Resource
grand_parent: Resources
permalink: /resources/code_terminology/mapping_tables
---

# Mapping Tables

These mapping tables are used to facilitate the translation of codelists from one terminology/classification into another. Please note translation is only valid in one direction.


| From | To | Mapping files (Box) | Documentation | Source |
| --- | --- | --- | --- | --- |
| READ V2 | SNOMED-CT | [RcSctMap2 (2020-04-01)](https://hdruk.app.box.com/file/1037487316847)<br><br>[RcSctMap (2020-04-01)](https://hdruk.app.box.com/file/1037487039479)<br><br>[RsSCtMap_enhanced (2020-04-01)](https://hdruk.app.box.com/file/1037490920256)<br><br>[RCTermSctMap (2020-04-01)](https://hdruk.app.box.com/file/1037487084578)<br><br>[RCMap (2020-04-01)](https://hdruk.app.box.com/file/1037487634013) | <a href="https://hdruk.app.box.com/file/1037487029225" target="_blank">Data Migration Subpack</a>.<br><br>The availability of concept and term IDs in the codelist to be mapped will determine which mapping file and methodology to use. Guidance in documentation. | <a href="https://isd.digital.nhs.uk/trud/users/guest/filters/0/categories/9/items/9/releases" target="_blank">NHS Data Migration - TRUD</a> |
| READ V2 | CTV3 | [RctCtv3Map (2020-04-01)](https://hdruk.app.box.com/file/1037487065886) | <a href="https://hdruk.app.box.com/file/1037489098360" target="_blank">Data Migration Subpack</a>. | <a href="https://isd.digital.nhs.uk/trud/users/guest/filters/0/categories/9/items/9/releases" target="_blank">NHS Data Migration - TRUD</a> |
| CTV3 | SNOMED-CT | [RctSctMap2 (2020-04-01)](https://hdruk.app.box.com/file/1037490082512) | <a href="https://hdruk.app.box.com/file/1037488080376" target="_blank">Data Migration Subpack</a>. | <a href="https://isd.digital.nhs.uk/trud/users/guest/filters/0/categories/9/items/9/releases" target="_blank">NHS Data Migration - TRUD</a> |
| CTV3 | READ V2 | [Ctv3RctMap (2020-04-01)](https://hdruk.app.box.com/file/1037484381812) | <a href="https://hdruk.app.box.com/file/1037482613089" target="_blank">April 2018 Release Contents</a>. | <a href="https://isd.digital.nhs.uk/trud/users/guest/filters/0/categories/9/items/9/releases" target="_blank">NHS Data Migration - TRUD</a> |
| CTV3 | ICD-9/ICD-10 | [v3 files (2018-04-01)](https://hdruk.app.box.com/folder/176838169027) | <a href="https://hdruk.app.box.com/file/1037486354814" target="_blank">Data Migration Subpack</a>. | <a href="https://isd.digital.nhs.uk/trud/users/guest/filters/0/categories/9/items/255/releases" target="_blank">NHS UK Read Codes Clinical Terms Version 3, Cross Maps - TRUD </a> |
| SNOMED-CT | OPCS-4.8 | [Mapping file (2021-03-24)](https://hdruk.app.box.com/file/1037492547115) | <a href="https://hdruk.app.box.com/file/1037482006410" target="_blank">SNOMED CT to ICD-10 and OPCS-4 Retired Reference Sets</a>. | <a href="https://isd.digital.nhs.uk/trud/users/guest/filters/0/categories/26/items/439/releases" target="_blank">SNOMED CT UK Clinical Edition Cross-map Historical Files, RF2: Full - TRUD  </a> |
| SNOMED-CT | ICD-10 (4th ed) | [Mapping file (2018-10-01)](https://hdruk.app.box.com/file/1037607499241) | <a href="https://hdruk.app.box.com/file/1037600604744" target="_blank">SNOMED CT to ICD-10 and OPCS-4 Retired Reference Sets</a>. | <a href="https://isd.digital.nhs.uk/trud/users/guest/filters/0/categories/26/items/439/releases" target="_blank">SNOMED CT UK Clinical Edition Cross-map Historical Files, RF2: Full - TRUD  </a> |
| BNF | SNOMED-CT | [Mapping file (2022-10-17)](https://hdruk.app.box.com/file/1054128120695) | <a href="https://hdruk.app.box.com/file/1054131830717" target="_blank">BNF/SNOMED Guidance Document</a>. | <a href="https://www.nhsbsa.nhs.uk/prescription-data/understanding-our-data/bnf-snomed-mapping" target="_blank">BNF SNOMED mapping - NHSBSA  </a> |