Related classifications in the WHO-FIC are those that partially refer to the reference classifications, e.g. only at specific levels. They include: International Classification of Primary Care (ICPC) ICPC-2 PLUS Anatomical Therapeutic Chemical Classification System with Defined Daily Doses (ATC/DDD) Assistive products — Classification and terminology (ISO9999:2022). WHO adopted ISO9999 as a related classification in 2003, however, the International Organization for Standardization (ISO) remains responsible for maintaining ISO9999. International Classification for Nursing Practice (ICNP) Historic FIC classifications ICD versions before ICD-9 are not in use anywhere. ICD-9 was published in 1977, and superseded by ICD-10 in 1994. The last version of ICD-10 was published in 2019, and it was replaced by ICD-11 on 1 January 2022. 35 of the 194 member states have made the transition to the latest version of the ICD. The International Classification of Procedures in Medicine (ICPM) is a procedural classification that has not updated since 1989, and will be replaced by ICHI. National adaptions of the ICPM includes OPS-301, which is the official German procedural classification. International Classification of External Causes of Injury (ICECI) was last updated in 2003 and, with the development ICD-11, is no longer maintained. The concepts of ICECI are represented within ICD-11 as extension codes. Other medical classifications Diagnosis The categories in a diagnosis classification classify diseases, disorders, symptoms and medical signs. In addition to the ICD and its national variants, they include: Diagnostic and Statistical Manual of Mental Disorders (DSM) DSM-IV Codes DSM-5 International Classification of Headache Disorders 2nd Edition (ICHD-II) International Classification of Sleep Disorders (ICSD) Online Mendelian Inheritance in Man, database of genetic codes Orchard Sports Injury and Illness Classification System (OSIICS) Read codes SNOMED CT Procedure The categories in a procedure classification classify specific health interventions undertaken by health professionals. In addition to the ICHI and ICPC, they include: Australian Classification of Health Interventions (ACHI) Canadian Classification of Health Interventions (CCI) Current Procedural Terminology (CPT) Health Care Procedure Coding System (HCPCS) ICD-10 Procedure Coding System (ICD-10-PCS) OPCS Classification of Interventions and Procedures (OPCS-4) Drugs Drugs are often grouped into drug classes. Such classifications include: RxNorm Anatomical Therapeutic Chemical Classification System Medical Reference Terminology National Pharmaceutical Product Index National Drug File-Reference Terminology (NDF-RT) National Drug File-Reference Terminology was a terminology maintained by the Veterans Health Administration (VHA). It groups drug concepts into classes. It was part of RxNorm until March 2018. Medication Reference Terminology (MED-RT) Medication Reference Terminology (MED-RT)