The document discusses the International Classification of Diseases (ICD), which is the international standard diagnostic tool used for epidemiology, health management, and clinical purposes. The ICD provides diagnostic codes to classify diseases, injuries, and other health conditions. It is revised every 10 years by the World Health Organization. The current version is ICD-10, approved in 1990. ICD-10 organizes diseases into 21 chapters based on affected body system or condition type. It uses alphanumeric codes for classification, with letters corresponding to chapters and numbers providing further subcategories. The ICD aims to standardize health data collection globally.