International statistical classification of diseases and related health problems

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The International Statistical Classification of Diseases and Related Health Problems ( ICD , English: International Statistical Classification of Diseases and Related Health problem ) is the most important, internationally recognized classification system for medical diagnoses.

It is published by the World Health Organization (WHO) and is often referred to as the International Classification of Diseases for short .

The future ICD-11 was approved by the World Health Assembly in May 2019 after the publication of a first version in June 2018 and will come into force on January 1, 2022. It is not yet possible to make any statements about the specific time of the introduction of the ICD-11 in Germany.

The current, internationally valid edition is ICD-10-WHO Version 2019. One limitation of the ICD-10 is that it defines illnesses solely through individual symptoms and diagnosis. The current disease status (consequences of the disease for the patient's ability to function, etc.) is not taken into account - although this is often very important for treatment and for assessing the severity of the health impairment. Therefore, the “ International Classification of Functioning, Disability and Health ” (ICF) was developed as an extension , which supplements the ICD with these aspects.
In tumor or cancer registers, tumor diagnoses are encoded according to the ICD-O .

In German-speaking countries

In Germany, on the are contractual medical and contract psychotherapeutic participating care physicians and psychotherapists, or it led bodies shall diagnoses according to ICD-10-GM (German Modification) to encrypt. The legal basis for this is Section 295, Paragraph 1, Clause 2 of Book Five of the Social Code (billing of medical services). The ICD-10-GM version 2020 published by the German Institute for Medical Documentation and Information (DIMDI) has been binding for the encryption since January 1st, 2020. Austria currently uses the ICD 10 BMASGK 2020. A change to ICD-11 is aimed at as soon as a German version of the new version is available. The German Modification is used in Switzerland and has been translated into French and Italian for this purpose.

Mental disorders

For the diagnosis of mental disorders there is the International Classification of Mental Disorders ( fifth chapter of the ICD-10 ) and, in parallel, the DSM-5 (a psychiatric classification system in the USA). Both are largely compatible, which means that diagnoses can be recoded between the systems. The WHO also publishes some manuals on this, e.g. B. the clinical-diagnostic guidelines (“blue book”) and the diagnostic criteria for research and practice (“green book”).


When statistics on causes of death were first compiled in the 19th century , the problem of a uniform classification arose. The first nomenclature of diseases was jointly developed in the 19th century by the English epidemiologist and co-founder of medical statistics William Farr (1807–1883) and the Geneva doctor Marc d'Espine , which later became the basis for the first ICD version.

The first version of the ICD was issued by the French government in 1900 , which was then revised and expanded at regular intervals. From the fourth version (ICD-4 from 1929) to the first post-war version (the ICD-6 from 1948) the health section of the League of Nations was the editor. Until then, the classification was limited to diseases that were possible causes of death.

The ICD has been published by the WHO since the sixth version and for the first time it also contained non-fatal diseases and injuries, including a. a separate chapter on mental disorders. The revision for the ICD-7 took place in 1955 in Paris and for the ICD-8 in 1965 in Geneva. Up to the ICD-9 of 1976, revised editions were made about every ten years, as changes and additions became necessary due to medical advances. Work on the current tenth edition began in 1983 and was completed in 1992. The currently (2019) valid international edition is the ICD-10 in the 2019 version.

Some states such as Germany, Austria, the United States, and Australia use country-specific ICD extensions or special editions. In the USA , a version ICD-9-CM ( clinical modification ) adapted to clinical needs is popular. In Austria the version ICD-10 BMG 2014 is used.

Situation in individual countries


In the GDR , the coding of diagnoses for both inpatient and outpatient treatment was carried out from 1952 onwards according to the current classification as an entry in the SV booklet . In 1986, the ICD-9 was used for the first time in the Federal Republic of Germany to encrypt diagnoses in hospitals.

According to § 295 (1) and § 301 (2) Fifth Book of the Social Security Code for Germany, the ICD is legally binding and is used to encode diagnoses in outpatient and inpatient care.

A Germany-specific version that deviates from the WHO version (ICD-10-SGB-V) was initially used from 2000 to 2003. Since 2004 the German ICD edition has been called ICD-10-GM (German modification) . In addition to the three-digit coding commonly used in clinical practice, there is also a four-digit detailed system (ICD-10-GM (VAS)).

It is published by the German Institute for Medical Documentation and Information (DIMDI). Older ICD versions used in East and West Germany are also archived and viewed there. Since the ICD-GM, in addition to adjustments by the World Health Organization (WHO), also takes into account suggestions from specialist societies, professional associations, hospitals and health insurance companies, which lead to new CD codes being added, deletions, clarifications and editorial adjustments, DIMDI, in contrast to the WHO, makes every year a new legally binding version. The ICD-10-GM Version 2020 published by DIMDI has been binding for encryption since January 1, 2020 .

In addition, there is an alphabetical directory for the ICD-10-GM in Germany, the so-called diagnostic thesaurus. There are special editions for various specialist areas (pediatrics, neurology). The current ICD-10 WHO version continues to apply in Germany for the coding of causes of death, since January 1, 2019 the 2019 edition.

In Germany, the ICD-10 code can be supplemented with an appended letter code in the outpatient area:

  • Safety:
    • A = exclusion of such a disease
    • G = confirmed diagnosis
    • V = suspected
    • Z = symptom-free final state after illness
  • Localization:
    • R = right
    • L = left
    • B = on both sides

According to Section 295, Paragraph 1 and Section 301, Paragraph 2, Fifth Book of the Social Security Code , contract doctors, contract psychotherapists and hospitals in Germany are obliged to code diagnoses in accordance with ICD. In the early days this was mostly done by doctors, today this task is also performed by coding specialists . A diagnosis-related group (DRG, diagnosis- related case group) is calculated from the ICD and OPS codes , so that case-related and diagnosis-related billing is possible. The ICD, together with the OPS - encryption for hospitals, form the basis of the DRG system, which was introduced in Germany in 2003 as the basis for calculating the compensation for services. The aim of this new system is to obtain a means of controlling the cost development despite the increasing burden on the health system due to demographic developments .

The XML- based markup language ClaML exists for the systematic EDP-compatible classification .


Since 2013, the use of the Germany-specific version ICD-10-GM 2012, which differs from the WHO version, has been mandatory for all service providers throughout Switzerland for coding the diagnoses. Previously the ICD-10-GM 2010, in exceptional cases ICD-10-WHO was used.


The ICD-10 is a uniaxial and mono-hierarchical classification system and is available in three volumes:

  • Volume I: Systematic Directory
  • Volume II: Regulations
  • Volume III: Alphabetical Index

It is divided into:

  • a three-digit general system (for example A95: yellow fever)
  • a four-digit detailed system (for example A95.0: bush yellow fever)
  • occasionally five-digit refinements (e.g. M23.31: Other meniscus damage, anterior cruciate ligament or anterior horn of the medial meniscus)

These "subordinate five-digit key numbers" may be replaced by the "higher-level four-digit key numbers" in the outpatient area, despite the resulting loss of information. There one speaks of the so-called five - digit code .

The notation is alphanumeric . The first digit is a letter, the digits two to five contain digits. The fourth digit is separated from the third digit by a point. This point must be left out in correspondence with the German Pension Insurance .

The areas U00 – U49 and U50 – U99 are reserved for expansions or research purposes. The ICD-10 contains:

  • 22 disease chapters
  • 261 disease groups (for example E10 – E14: diabetes mellitus)
  • 2,037 three-digit disease classes (categories) (for example E10.-: Primarily insulin-dependent diabetes mellitus [type I diabetes])
  • 12,161 four-digit disease classes (subcategories) (for example: E10.1: Primarily insulin-dependent diabetes mellitus [type I diabetes] with ketoacidosis)

The classification criteria alternate between topography , etiology and pathology .

The classification itself has no temporal or dynamic aspects, but only includes a description of time-invariant features. The systematic directory contains an additional classification (M-axis) with which neoplasms can be classified histologically . This is a six-digit key that begins with the letter "M". This is followed by four digits to code the neoplasm, followed by a slash (/) and a number to code the pathological behavior (for example: M8051 / 3: verrucous carcinoma, N / A). The structure of the M-axis largely corresponds to the ICD-O or SNOMED classification .

Disease chapter

chapter notation designation
I. A00-B99 Certain infectious and parasitic diseases
II C00-D48 Neoplasms (e.g. tumors, etc.)
III D50-D89 Diseases of the blood and the blood-forming organs and certain disorders that involve the immune system
IV E00-E90 Endocrine , nutritional and metabolic diseases
V F00-F99 Mental and behavioral disorders
VI G00-G99 Nervous system diseases
VII H00-H59 Diseases of the eye and the appendages
VIII H60-H95 Diseases of the ear and mastoid process
IX I00-199 Diseases of the circulatory system
X J00-J99 Respiratory system diseases
XI K00-K93 Diseases of the digestive system
XII L00-L99 Diseases of the skin and subcutaneous tissue
XIII M00-M99 Diseases of the musculoskeletal system and connective tissue
XIV N00-N99 Diseases of the genitourinary system
XV O00-099 Pregnancy , childbirth and the puerperium
XVI P00-P96 Certain conditions that originate in the perinatal period
XVII Q00-Q99 Congenital malformations , deformities and chromosomal abnormalities
XVIII R00-R99 Symptoms and abnormal clinical and laboratory findings not elsewhere classified
XIX S00-T98 Injuries , poisoning and certain other consequences of external causes
XX V01-Y98 External causes of morbidity and mortality
XXI Z00-Z99 Factors that affect health and lead to utilization of the health care system
XXII U00-U85 Key numbers for special purposes

Double classification

Some diseases are shown in ICD-10 with a double classification. The primary classification is based on the etiology , the secondary according to the organ manifestation. In the system, the primary key is shown with a cross (+), the secondary key with an asterisk (*). This notation is known as the cross-star system.

Example: The ICD-10 code A17.0 + (tuberculous meningitis ) is an infectious disease in terms of etiology and a disease of the nervous system in terms of organ manifestation (G01 *).

Example: An ophthalmologist who treats diabetic retinopathy and not the underlying disease ( diabetes mellitus ) is primarily interested in the clinical secondary key:

  • Etiology: E10.30 + type I diabetes mellitus with eye complications, not described as derailed.
  • Organ manifestation: H36.0 * Diabetic retinopathy.

The cross notation is used for statistical purposes. The asterisk notation has a broader clinical relevance and is sometimes used. a. used for activity allocation.


In Germany, as early as 1996, the statutory health insurance bill should have been based exclusively on ICD-10 encryption. After massive resistance from the medical profession, the ICD-10 was initially introduced as a voluntary option; the use of a revised version has been mandatory since 2000.

The main criticisms of the ICD are:

  • It was feared that data-based evaluation procedures could undermine the medical confidentiality obligation (“transparent patient”).
  • The possibility of a machine evaluation of the accounting data should make the medical activity transparent and controllable to an inadmissible degree ("transparent doctor").
  • The structure does not correspond to medical or practical aspects, but merely follows statistical requirements. For example, under K, all diseases of the digestive system are summarized (from the teeth to the anus) that affect very different specialist groups in medical practice. On the other hand, important gastrointestinal diseases such as carcinomas , which are generally classified under C.
  • The national applications of the ICD are incomplete. For example, codes were temporarily excluded in the Federal Republic of Germany. The international comparability of the causes of illness is therefore limited.
  • The use of some diagnoses, especially under Z, could be an inadmissible disclosure of the patient's personal situation and environment, e.g. B. Information about influences from the family or professional environment.
  • Not every symptom corresponds to an ICD clinical picture; this makes it difficult for the doctor to provide clear information if initially no clinical picture fits one hundred percent.
  • The ICD is also questionable from a statistical point of view because it does not clearly differentiate between diagnoses and symptoms. ( Hematuria [ICD-10: D68.3] is a symptom that can have various causes. This leads to inaccuracy because formally the symptom and the cause should always be coded, but in practice both are rarely coded.)

Furthermore, it is criticized that ICD contributed or still contributes to the pathologization of homosexuality and bisexuality (deleted from ICD-9 in 1990) and transsexuality (no longer included in ICD-11) . France therefore banned the classification of transsexual people under F64.0 as stigma and discrimination by decree . The euro Council has called in its resolution 2048 of 22 April 2015 for the legal and social equality of trans people, the 47 member states, among other things, to cancel all classifications as mental disorders in national classifications and to demand the cancellation even at the WHO. As early as 2011, the European Parliament asked the European Commission and the WHO to remove gender identity disorders from the list of mental and behavioral disorders and to ensure a non-pathologizing reclassification in the negotiations on the 11th revision of the International Classification of Diseases (ICD-11).

Web links

German Institute for Medical Documentation and Information (DIMDI)

World Health Organization (WHO):

Individual evidence

  1. WHO releases new International Classification of Diseases (ICD-11) . , News Medical, accessed June 19, 2018.
  2. World Health Assembly adopts ICD-11 . Deutsches Ärzteblatt from May 27, 2019.
  3. DIMDI - ICD-11 . DIMDI , accessed November 27, 2019.
  4. Michael Linden : Illness and Disability - The ICF Model . In: The neurologist . tape 86 , no. 1 , January 1, 2015, p. 29–35 , doi : 10.1007 / s00115-014-4112-9 ( [accessed January 2, 2018]).
  5. International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3) , accessed November 20, 2019.
  6. a b Federal Ministry of Health: Announcement according to §§ 295 and 301 of the fifth book of the Social Security Code (SGB V) on the application of the diagnosis code from October 24, 2019. Retrieved on March 20, 2020 .
  7. Performance-oriented hospital financing Medical documentation Coding instructions up to and including 34th circular on January 1, 2020 p. 8 (PDF), accessed on March 6, 2020
  8. ^ ICD implementation in the EU. Retrieved June 5, 2019.
  9. Medical coding and classifications information page of the Swiss Federal Statistical Office . Retrieved June 5, 2019.
  10. ^ A b Hans-Ulrich Wittchen : Clinical Psychology & Psychotherapy . Springer, 2011, ISBN 978-3-642-13017-5 , chap. 2 , p. 40–42 ( limited preview in Google Book search).
  11. Isabel dos Santos Silva: Cancer Epidemiology: Principles and methods International Agency for Research on Cancer , Lyon, France 1999, ISBN 92-832-0405-0 .
  12. DIMDI: ICD-10: History and Outlook. Retrieved May 13, 2018 .
  13. ^ WHO: History of the development of the ICD . Retrieved May 13, 2018 .
  14. Overview ICD-10 of the WHO
  15. ^ Diagnosis codes in the social security card of the GDR. In: DIMDI, accessed January 2, 2020 .
  16. ^ ICD-9 - International Classification of Diseases, 9th Revision. In: DIMDI, accessed July 19, 2016 .
  17. DIMDI: ICD-10-GM. DIMDI, accessed July 20, 2018 .
  18. ^ Association of Statutory Health Insurance Physicians in Bavaria: Coding of diagnoses with ICD-10-GM. KVB, accessed on July 20, 2018 .
  19. ICD-10-WHO - version history In:
  20. ICD-10. In: H + The Hospitals of Switzerland, accessed on August 5, 2020 .
  21. ^ ICD-10-GM 2010 Systematic Directory , Deutscher Ärzteverlag , Cologne 2010, p. LXXI.
  22. DL. Jones: Classification of velopharyngeal status in speakers with cleft palate. The relationship between temporal aspects of oral-nasal balance and classification of velopharyngeal status in speakers with cleft palate . In: Cleft Palate Craniofac J. , 2000 Jul, 37 (4), pp. 363-369, PMID 10912715 .
  23. Kurt Kieselbach: The "transparent patient" becomes a bone of contention . In: Die Welt , July 22, 1999.
  24. Resolution 2048 (2015): Discrimination against transgender people in Europe PDF. Retrieved May 2, 2015.
  25. Christina Laußmann: Historical resolution for the rights of trans * people passed. German Aids Aid, April 23, 2015.
  26. Resolution of the European Parliament of December 12, 2012 on the situation of fundamental rights in the European Union (2010-2011) (2011/2069 (INI)), Sexual orientation and gender identity, Recommendation No. 98 .