Histology Course Department of Pathology, University of Zurich Histology Course
 
 
INTRODUCTION TO THE INTERNATIONAL CLASSIFICATION OF DISEASES (ICD)
 
 
Website of the WHO about ICD-10
 
 
ICD-10

"ICD-10 was endorsed by the Forty-third World Health Assembly in May 1990 and came into use in WHO Member States as from 1994. The classification is the latest in a series which has its origins in the 1850s. The first edition, known as the International List of Causes of Death, was adopted by the International Statistical Institute in 1893. WHO took over the responsibility for the ICD at its creation in 1948 when the Sixth Revision, which included causes of morbidity for the first time, was published.

The ICD has become the international standard diagnostic classification for all general epidemiological and many health management purposes. These include the analysis of the general health situation of population groups and monitoring of the incidence and prevalence of diseases and other health problems in relation to other variables such as the characteristics and circumstances of the individuals affected.

It is used to classify diseases and other health problems recorded on many types of health and vital records including death certificates and hospital records. In addition to enabling the storage and retrieval of diagnostic information for clinical and epidemiological purposes, these records also provide the basis for the compilation of national mortality and morbidity statistics by WHO Member States."

(from www.who.int/classifications/icd/en)

ICD-10 contains 21 chapters. The code consists of four digits: First a letter, which is assigned (with excepitons) to a certain chapter. The chapters are divided into similar groups of 3-digit categories. The fourth digit describes more specific information about special states and localisations.
 
Special characters like† / * are used as an indicator for the "etiology-key-number" respectively "manifestation-key-number" for special indications which have a double classification.
 
 

ICD-O

ICD-O is principally used in tumour or cancer registries for coding the site (topography) and the histology (morphology) of neoplasms, usually obtained from a pathology report:
 
The topography axis uses the ICD-10 classification of malignant neoplasms (except those categories which relate to secondary neoplasms and to specified morphological types of tumours) for all types of tumours, thereby providing greater site detail for nonmalignant tumours than is provided in ICD-10. An additional (non-ICD-10) topography code is provided to enable the site of haematopoietic and reticuloendothelial tumours to be identified.
 
The morphology axis provides five-digit codes ranging from M-8000/0 to M-9989/3. The first four digits indicate the specific histological term. The fifth digit after the slash or solidus (/) is a behaviour code which indicates whether a tumour is malignant, benign, in situ, or uncertain whether benign or malignant.

(from www.who.int/classifications/icd/adaptations/oncology/en/index.html)

Web resources: www.pubcan.org