Skip to main content [accesskey + 1] Skip to navigation [accesskey + 2] Skip to sidebar [accesskey + 3]


Local Servicelinks


Alpha-ID-SE - Scope of application "Rare Diseases"

DIMDI publishes, in the context of the project "Rare diseases coding", a test file of the Alpha-ID (starting with version 2015) which contains the Orpha number in addition to the ICD-10-GM code for rare diseases.

The Alpha-ID-SE (rare diseases) allows a simplified, uniform and standardised coding of rare diseases according to ICD-10-GM on one hand, and to the Orpha number on the other hand. This improves documentation and leads to an adequate representation of rare diseases in the German healthcare sector. Furthermore, the Orpha numbers allow connections to reference systems for rare diseases throughout Europe.

DIMDI also works on the improvement of the codification of rare diseases (RD) in the framework of the European project "Rare Disease Action" (RD-Action). The primary aim of this project is to improve the visibility of rare diseases at European level.

Rare Diseases, ICD-10 and Orphanet

What are rare diseases?

There is no widely accepted definition for rare diseases. In Europe a prevalence of not more than 5 affected persons per 10.000 is generally regarded as the appropriate threshold, according to the Regulation of the European Parliament and of the Council on orphan medicinal products.

Regulation (EC) No 141/2000 of the European Parliament and of the Council of 16 December 1999 on orphan medicinal products

Coding rare diseases with ICD-10-GM: unspecific in most cases

More than 4 million people in Germany suffer from a rare disease. It is estimated that about 8000 distinct rare diseases affect the population worldwide. Rare diseases are so numerous that as a whole they are as frequent as a widespread disease. Nonetheless, rare diseases are barely perceptible from an epidemiological perspective.

Only few rare diseases can be specifically coded with ICD-10, in other words, they have an own code. Most of them are classified as "inclusions" of an unspecific ICD-10 code. Therefore a large number of rare diseases can no longer be identified by means of the ICD-10 code. Moreover, many rare diseases are still not listed in the Alphabetical Index of ICD-10.

In order to make rare diseases visible in epidemiology, they must be coded as specifically and precisely as possible.

Orphanet rare disease nomenclature as a specific coding system for rare diseases

Orphanet, a European reference portal for information on rare diseases and orphan drugs, offers a specific coding system with its nomenclature. All rare diseases in this nomenclature have been assigned a consecutiv, specific identification number, the  Orpha number (so-called "Orphacode").

Via its website Orphadata, Orphanet provides information regarding its nomenclature system and the connection to other code systems and terminologies such as ICD-10, MeSH, OMIM, MedDRA, and UMLS - free of charge.

The European Council has recommended in 2014 that all Member States of the European Union "[…] should consider adding Orpha codes to their country’s health information system […]".

Recommendation on Ways to improve Codification for Rare Diseases in Health Information Systems

Zum Seitenanfang zurück


National DIMDI Project "Kodierung von Seltenen Erkrankungen" (Rare diseases coding)

In order to code rare diseases specifically in Germany, Orpha numbers should be used in addition to the ICD-10-GM code which is compulsory in inpatient and outpatient routine coding. Therefore coders would need to use two coding systems.

The goal of the DIMDI project "Rare diseases coding" is to improve the coding of rare diseases and to simplify this "double" coding process. The project is an initiative in the context of the National Action Plan for People with Rare Diseases. It was initiated in July 2013, was set up for three years and has been extended until the end of June 2019.This project is financed by the Federal Ministry of Health (BMG).

Addition of rare diseases to the Alphabetical Index of ICD-10-GM and Alpha-ID

This project initially reviews whether all rare diseases listed in the Orphanet nomenclature are included in the Alphabetical Index of ICD-10-GM. Diseases that are not included will be added and assigned to an ICD-10-GM category. In addition, there will be a reconciliation with Orphanet for all ICD-10 codes that are already mapped to the rare diseases of the Orphanet nomenclature.

This first step will lead to a better representation of rare diseases in ICD-10-GM and thus to improved coding.

When a rare disease is added to the software version of the Alphabetical Index of ICD-10-GM, a specific identification number is assigned to every term. With this specific identification number and the ICD-10-GM code rare diseases are then also included in the Alpha-ID file, which DIMDI publishes on an annual basis.

Test file Alpha-ID-SE with Orpha numbers

To further improve the documentation of rare diseases, Orpha numbers are added to the rare disease entries of the Alpha-ID and published in a project-specific test file, the Alpha-ID-SE. This connection of ICD-10-GM codes and Orpha numbers in the Alpha-ID-SE makes it possible to code rare diseases in Germany in a more differentiated and specific manner by means of a file.

The "Musterdatensatz", an extract of the test file Alpha-ID-SE is a sample data set that only includes rare diseases with the assigned Orpha number. A test implementation of this "Musterdatensatz" is planned in 4 selected reference centers for rare diseases as part of the project. As a result of the project DIMDI will issue a recommendation to a nationwide routine implementation.

The following exemplary extract from the test file Alpha-ID-SE shows that synonymous terms of rare diseases such as, for instance, Fibrodysplasia ossificans progressiva and Münchmeyer-Syndrom have the same Orpha number (337) and the same ICD-10-GM code (M61.19), but different Alpha-ID codes: This is the concept of Alpha-ID, every text entry has its own Alpha-ID code.

Please note that the Alpha-ID is based on the Alphabetical Index of the ICD-10-GM, and that Alpha-ID codes are only assigned to diagnostic terms in German language. Therefore the use of Alpha-ID codes for files in other languages does not apply.

The test file also shows that several distinct rare diseases such as, for instance, the Zerebro-hepato-renales Syndrom (Cerebrohepatorenal syndrome) and Lymphödem mit Hypoparathyreoidismus (Lymphedema-hypoparathyroidism syndrome) may be assigned the same ICD-10-GM code (Q87.8), but aside from different Alpha-ID codes may also have different Orpha numbers (912 and 1563 respectively). This example shows that distinguishable diseases can not be identified by using only the ICD-10-GM code.

The example of the test file below also clarifies the relation between the ICD-10-GM code and the Orpha number, for instance: diseases like Apfelschalensyndrom (Apple peel syndrome), Jejunalatresie (Jejunal atresia) and Dünndarmatresie (Atresia of small intestine), may all have the same Orpha number (1201) but in some cases a different ICD-10-GM code (in this case Q41.1 or Q41.9). It illustrates the diverse criteria two different systems, like the Orphanet rare disease nomeclature and the ICD-10-GM use to classify diseases. In this case the ICD-10-GM uses the localization as further classification criteria (Q41.1 concerns the atresia of jejunum and Q41.9 the atresia of the small intestine, part unspecified).

In case of the synonyms Intestinale Lipodystrophie (Intestinal lipodystrophy) and Whipple-Krankheit (Whipple disease), which have the same Orpha code (3452), one synonym is coded with a single ICD-10-GM code (K90.8), the other one with an additional asterisk code (K90.8+ M14.89*) to indicate the manifestation.

Excerpt from the test file Alpha-ID-SE/ "Musterdatensatz"
Alpha-ID Code ICD-10-GM Code

ICD-10-GM Additional

(Asterisk) Code

Orpha Number Diagnostic Term
I5821 K90.8 unbesetzt 3452 Intestinale Lipodystrophie
I24937 K90.8+ M14.89* 3452 Whipple-Krankheit
I32050 M61.19 unbesetzt 337 Fibrodysplasia ossificans progressiva
I81949 M61.19 unbesetzt 337 Münchmeyer-Syndrom
I82889 Q41.1 unbesetzt 1201 Apfelschalen-Syndrom
I118177 Q41.1 unbesetzt 1201 Jejunalatresie
I17291 Q41.9 unbesetzt 1201 Dünndarmatresie
I9222 Q87.8 unbesetzt 912 Zerebro-hepato-renales Syndrom
I118259 Q87.8 unbesetzt 1563 Lymphödem mit Hypoparathyreoidismus

The test file Alpha-ID-SE is a basis for the completion of other actions of the National Plan of Action for People with Rare Diseases, for example the creation of a registry prototype or the "se-atlas" [a web portal that maps care providers for persons with rare diseases].

Furthermore, the file is available to any user who strives to create a differentiated depiction of rare diseases. For example, the access to information from Orphanet regarding certain rare diseases can be simplified via the connection of ICD-10-GM codes and Orpha numbers by providing corresponding references to Orphanet for the user during the coding process with ICD-10-GM.

The project-specific test file Alpha-ID-SE is included as electronic version (TXT (CSV) in the ZIP file for Alpha-ID. It is updated annually. The currently valid version is effective from the beginning until the end of a calendar year. The "Musterdatensatz"  2018 includes all 4.148 entries of Alpha-ID-SE for rare diseases thus far. In the case of corrections during this period of validity you will be informed by our Newsletter DIMDI News.

Further information on our website
Additional information on the web
Zum Seitenanfang zurück


International EU Project "RD-Action" (Rare Disease Action)

DIMDI works on the improvement of the codification of rare diseases (RD) in the framework of the European project „Rare Disease Action” (RD-Action).

The cooperation of different countries in the thematic field of RD proved to be useful in the past. RD-Action large geographical coverage is key to success since it promotes the transfer of European recommendations into national policies and the collection of information and concerns from Member States (MS) to the Commission Expert Group on Rare Diseases (CEGRD), thus to the European Commission.

With 34 beneficiaries and 30 collaborating partners from 40 participating countries, the RD-Action aims at creating a consistent European way of meeting challenges in the field of RD. Besides EU-countries, other European countries like Iceland and Switzerland as well as non-European countries like Canada and Australia are participating in the RD-Action and thus involved in international developments in the field of RD. One objective of the RD-Action is to support the development and sustainability of the Orphanet database. A second objective is the contribution to solutions to ensure an appropriate codification of RD in health information systems across Europe. Besides that, the work on priority issues for people living with RD by implementing the actions defined in the EU Council Recommendation on an action in the field of RD and to ensure the sustainability of these actions as well as supporting the work of the CEGRD are further objectives.

The 3-year European Joint Action started in June 2015 and is co-financed by the European Commission.

Content of the project

RD-Action consists of 6 Workpackages (WP). DIMDI leads the WP 5, Steering, maintaining and promoting the adoption of Orphacodes across MS.

Figure: Workpakages of the RD-Action

Figure shows 6 workpakages (WP) of the RD-Action as 6 hexagonal combs containing the respective title of the WP

Workpackage 5: Steering, maintaining and promoting the adoption of Orphacodes

With the recommendation of the European Council of 2009 on an action in the field of RD all MS should amongst others "aim to ensure that rare diseases are adequately coded and traceable in all health information systems […]":

COUNCIL RECOMMENDATION of 8 June 2009 on an action in the field of rare diseases (2009/C 151/02)

The RD-Action aims to put into effect this part of the council recommendation at European level.

The WP 5 can be divided into 4 different tasks. The tasks are building on each other in time and content. The following tasks are performed:

  • Task 5.1.    To define and set the necessary strategy and tools (i.e. coding rules) to implement the Orphacodes in the European countries.
  • Task 5.2.    Specifications of the required resources (i.e. Master file) for coding RD consistently across Europe.
  • Task 5.3.    Promoting the Orphacodes across MS by sharing coding tools and testing the master resource.
  • Task 5.4.    Plan for next steps needed to address long-term maintenance and sustainability of the resources and guidelines.

DIMDI is responsible for the achievement of task 5.2. Within this task the Master file should be developed. Comparable to the "Musterdatensatz", which is produced in the framework of the national project, the master file should enable an easy and standardized way to code RD across MS.

To ensure the progress of the project, deliverables have been scheduled. These are:

  • D 5.1.    Review document of existing technical implementations for RD coding of MS (published in May 2016)
  • D 5.2.    Standard procedures and guide for the coding with Orphacodes (published in May 2017)
  • D 5.3.    A European integrated master file (due in May 2018)
  • D 5.4.    A set of coding helping tools for rare diseases (due in May 2018)
  • D 5.5.    Draft recommendation for routine maintenance (due in May 2018)

All planned deliverables of the project are included in the table below.

 Abbildung enthält die geplanten Ergebnisse von Arbeitspaket 5 der Rare Disease Action im Projektverlauf nach Quartal über die Jahre 2015 bis 2018

The participation of DIMDI on the RD-Action enables the development of synergies and the exchange of experiences. Furthermore, it can be guaranteed that in the field of coding RD on national and international level the developments are promoted in a similar way and thus are in line with each other.

Additional information about the international EU project on the web

RD-Action - Data and policies for rare Disease

RD-Action - Leaflet and documents


Abbildung enthält das EU-Logo mit dem Text: Co-founded by the Health Programme of the European Union 


This website is part of the project / joint action '677024 / RD-ACTION' which has received funding from the European Union’s Health Programme (2014-2020).

The content of this website represents the views of the author only and is his/her sole responsibility; it can not be considered to reflect the views of the European Commission and/or the Consumers, Health, Agriculture and Food Executive Agency or any other body of the European Union. The European Commission and the Agency do not accept any responsibility for use that may be made of the information it contains.