The International Classification of Diseases (ICD) is a classification of diseases and medical conditions used throughout the world to code hospital admissions and deaths. This is so that information can be compared across the world in relation to specific medical conditions and diseases. Any codes will depend directly on the information available on the patient’s hospital medical notes or their death certificate. Even with a standard classification such as the ICD, the way information is recorded and the way codes are applied can mean that there could be differences across organisations and across countries, etc. However, there are rules around coding to minimise such differences.
The current version of the ICD is version 10.
The ICD 10 codes are used in England to record the primary diagnosis of or cause for the hospital admission, and the underlying cause of death. However, for both hospital admissions and deaths, secondary diagnoses or causes can also be applied to the admission or death. The secondary diagnoses can relate to other medical conditions or diseases that are influential of the person’s hospital care or death, but also to other situations such as the circumstances of the hospital visit or hospital admission. For instance, there are codes relating to maternity such as a women being in hospital in order to give birth to a baby, and codes relating to normal healthcare business such as the outpatient visit or admission being coded as being related to a screening appointment or an exploratory diagnosis appointment. However, there are also other external codes to record the circumstances such as hospital admission caused by a traffic accident, injury or fall. A person who falls and fractures their leg, and is subsequently admitted to hospital, will have a primary diagnosis of a fracture of the leg as this is the medical condition being treated, but there should have a secondary diagnosis coded a ‘fall’.