ICD-9 - International Classification of Diseases, Ninth Revision

The "International Classification of Diseases and Related Health Problems" (ICD-9) was developed by the World Health Organisation (WHO) and translated into German by the DIMDI. The abbreviation ICD stands for International Classification of Diseases; the figure 9 refers to its Ninth Revision.

In 1979, ICD-9 was introduced in the Federal Republic of Germany and the former German Democratic Republic, in separate version, as the basis for mortality statistics. It was in use until 1997 and replaced in January 1998 by ICD-10.

In the former German Democratic Republic, morbidity encoding also was performed on the basis of ICD-9 since 1979. In the Federal Republic of Germany, morbidity encoding was first introduced in 1986; it was first done using three-character codes, but turned to four-character in 1994 with ICD-9. In 1998, it was replaced by ICD-10. ICD-9 ("Ost") it not available in electronic version.

Structure of ICD-9

ICD-9 consists of two large parts, published in three separate volumes.

  • Volume I, Part A contains some introductory texts, the Tabular List of three-character categories (DAS), the Tabular List of inclusions and four-character subcategories (VAS) and the morphology code.
  • Volume I, Part B contains a general introduction to ICD, the encoding rules for mortality and morbidity, numerous encoding examples and also two additional tabular lists:
    • Additional classification "External causes of injuries and poisonings – E-classification
    • Additional classification for contact reasons: "Factors influencing health status and contact with health services" – V-classification
  • Volume II represents the Alphabetical Index with an extensive compilation of encoded diagnoses, encoded causes of injuries and with encoded poisonings and unwanted effects of medicinal drugs and chemical substances.



The inpatient sector in the United States of America uses a 3-volume version of ICD, partially extended to five-character codes: The International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM). Same as for ICD-9, Volume 1 contains the Tabular List of inclusions and four-character subcategories and Volume 2 the Alphabetical Index; in addition, a classification of medical procedures has been published as Volume 3 complete with a Tabular List and an Alphabetical Index.