5.1 International Classification of Diseases

Expected time: 30 minutes

ICD-10

We are now going to discuss how congenital anomalies are coded utilizing the International statistical classification of diseases and related health problems, tenth edition, also known as the ICD-10, and the Royal College of Paediatrics and Child Health (RCPCH) adaptation. The ICD-10 is developed and maintained by WHO, and is considered the international standard diagnostic classification system.

The most recent version of the ICD-10 is available on the WHO website (3) (http://apps.who.int/classifications/icd10external icon).

It is widely used in many countries as a classification system for diseases. It is useful in assisting with analysis and assessment of the health situation of population groups and for monitoring the incidence and prevalence of diseases and other health conditions.

ICD-10 codes are listed in alpha-numeric order and are described in detail. Classification of structural congenital anomalies is found in Chapter XVII: Congenital malformations, deformations and chromosomal abnormalities (Q00–Q99). Classification of haemolytic anaemias (thalassemia and sickle cell disorders) is found in Chapter III: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50–D89).

Modifications

The ICD-10 codes lack specificity for uniquely coding some congenital anomalies and most genetic syndromes. Therefore, some congenital anomalies surveillance programmes use their own local modification of the ICD-10 that includes additional codes for some specific congenital anomalies not found in the ICD-10, and add an extra digit to allow for more detailed coding of some anomalies and specificity of diagnoses.

As a result of this lack of specificity of ICD-10 codes, the RCPCH developed an adaptation of the ICD-10. Please refer to Chapter 5 of WHO/CDC/ICBDSR Birth defects surveillance: a manual for programme managers (4), for an example of this adaptation of the ICD-10. This adaptation is most commonly used by programmes carrying out public health surveillance of congenital anomalies.

Also, when the ICD-10 code is not specific enough, for example, “Q01.8 Encephalocele of other sites”, then using the classification developed by the RCPCH could be beneficial.

If possible, the use of codes for nonspecific diagnoses should be avoided. For example, try to avoid a code such as “Q01.9 Encephalocele, unspecified”; however, sometimes you do not have a choice.