Starting with the 2005 version, the ICD-10 Thesaurus of diagnostic terms ("Diagnosenthesaurus") has been continued as the Alphabetical Index to ICD-10-GM. The files are available under Downloads in the folder for the respective annual version of the ICD-10-GM under the subfolder "Alphabet" (Alphabetical Index).

Alphabetical Index to ICD-10-GM

The Alphabetical Index to ICD-10-GM (previously known as "Diagnosenthesaurs" - Thesaurus of diagnostic terms) makes working with ICD-10-GM considerably easier. With the 2006 version, the integration of the World Health Organisation Alphabetical Index (ICD-10-WHO) was completed. It now contains more than 75,000 alphabetically ordered ICD-encoded entries, which in the book version turn into more than 120,000 searchable texts. Alpha-ID, published by DIMDI from 2005 until 2020 and since 2020 by BfArM, uses the extensive compilation of diagnostic terms in the Alphabetical Index as the basis for a non-classifying diagnostic code.

The Alphabetical Index to ICD-10-GM can be used both in inpatient and in outpatient care; however, please note that in both care sectors of our healthcare system, different encoding rules apply in some instances. More information on this topic and some examples are provided in the preface to the Tabular List of ICD-10-GM under "Anleitung zur Verschlüsselung" (Encoding Instructions).

In the past, different versions of the thesaurus of diagnostic terms were published because of different encoding in the outpatient and inpatient sectors. The historical development is outlined in brief below.

• From version 2005: Alphabetical Index to ICD-10-GM of the respective year based on ICD-10-GM of the respective year for the outpatient and inpatient sector
• ICD-10 Thesaurus of diagnostic terms (Alphabetical Index) version 2004 based on ICD-10-GM version 2004 for the outpatient and inpatient sector
• ICD-10 Thesaurus of diagnostic terms version 4.0 based on ICD-10-SGB-V version 2.0 for the inpatient sector
• ICD-10 Thesaurus of diagnostic terms version 3.1 with some changes compared to version 3.0, also based on ICD-10-SGB-V version 1.3 for the outpatient sector
• ICD-10 Thesaurus of diagnostic terms version 3.0 based on ICD-10-SGB-V version 1.3 for the outpatient sector

ICD-10 Thesaurus of diagnostic terms (IDT) of the Central Research Institute of Ambulatory Health Care in Germany (ZI)

The IDT was developed by the Central Research Institute of Ambulatory Health Care in Germany (ZI) in an expert group under the scientific direction of Prof Dr W. Giere (University of Frankfurt/Main). From 1995, registered doctors in outpatien care were to encode diagnoses on invoices and incapacity certificates in accordance with ICD-10. However, it became apparent that in many instances the terms for diseases used in the classification were not suitable for encoding in daily routines. For that reason, ICD-10 was to be revised by the Central Federal Association of Statutory Health Insurance Funds, the National Association of Statutory Health Insurance Physicians (KBV) and the German Hospital Federation (DKG) and adapted to the requirements of doctors charged with the encoding. This is how the socalled "ICD-Basisschlüssel" (ICD base code) was developed. As a supplement, the ZI published the ICD Thesaurus of diagnostic terms in order to supply doctors in their surgeries with an alphabetical register of terms for diseases used in the German-language area. The disease names including the synonyms used by doctors were compiled from a range of different sources and supplemented with the respective official ICD code; version 1.1 comprised approx. 10,000 entries in naturally language. This was followed by versions 2.0, 2.1 and 2.2.

Transfer of rights to DIMDI from version 3.0

With version 3.0 (by then the number of diagnostic texts had grown to approx. 30,000), the rights to the IDT were transferred to the DIMDI. Since then, the DIMDI has been the editor, ensuring the ongoing maintenance and continuous development within the current structures.