Diagnosis Codes

Diagnosis Coding

In healthcare, diagnostic codes are used to group and identify diseases, disorders, symptoms, human response patterns, and medical signs, and are used to measure morbidity and mortality. As the plural with the name of this lemma indicates, there will be never one code for all purposes, but many codes for some distinct purposes each.

The codes may be quite frequently revised as new knowledge is attained. DSM changes some of its coding to correspond to the codes in ICD. In 2005, for example, DSM changed the diagnostic codes for circadian rhythm sleep disorders from the 307-group to the 327-group; the new codes reflect the moving of these disorders from the Mental Disorders section to the Neurological section in the ICD.


Commonly used diagnosis coding systems:

• ICD-9-CM (volumes 1 and 2 only. Volume 3 contains Procedure codes)
• ICD-10
• ICPC-2 (Also includes reasons for encounter (RFE), Procedure codes and process of care)
• ICSD, The International Classification of Sleep Disorders
• NANDA
• Diagnostic and Statistical Manual of Mental Disorders or DSM-IV (primarily psychiatric disorders)
• Mendelian Inheritance in Man (genetic diseases only)
• Read code used throughout United Kingdom General Practice computerised records
• SNOMED (D axis)