Changes to SNOMED CT and Read Codes (CTV3) for CFS, ME and PVFS

Post #327 Shortlink:

Recent changes to SNOMED CT for CFS, ME and PVFS

  • Correspondence between Forward-ME and UK Health and Social Care Information Centre
  • SNOMED CT retires Mental disorder parent for Chronic fatigue syndrome and ME
  • Projected changes to April 2016 release of Read Codes Clinical Terms Version 3 (CTV3)
  • Read Codes system to be phased out as part of wider SNOMED CT implementation

In addition to ICD-10, a number of terminology and electronic health and medical record systems are used in the UK in primary, secondary, and health and social care clinical settings, which include:

OPCS-4 (classification of Surgical Operations and Procedures)

SNOMED CT (Systematized Nomenclature of Medicine – Clinical Terms, a comprehensive, multilingual clinical terminology system)

Read Codes (a coded thesaurus of clinical terms for recording patient findings and procedures in health and social care IT systems across primary and secondary care, e.g. GP surgeries and reporting of pathology results).

The National Information Board (NIB) has specified that all primary care systems adopt SNOMED CT by the end of December 2016 and that SNOMED CT is to be used as the single terminology in all health care settings in England, with a projected adoption date for the entire health system of April 2020 [3].

You can access a public SNOMED CT browser here: IHTSDO browser

This is an online browser and does not require any software to be downloaded. You will need to accept the license and then select for the UK “Local Extension” of SNOMED CT. Click on the “Search” tab to enter clinical terms.

The SNOMED CT International Edition and “Local Extensions” for a number of other countries, including the US, are also available via the browser. All editions release new updates twice a year, on a staggered schedule. The Release schedule for the UK Extension is April and October.

Read Codes system to be retired

The Read Codes system of clinical terms has been used in the NHS since 1985. As part of the adoption of SNOMED CT in primary care, Clinical Terms Version 3 (CTV3) is being deprecated.

More information on the phasing out of Read Codes, here:

Retirement of Read Version 2 and Clinical Terms Version 3

Click link for PDF document Retirement Schedule

There was no new release for CTV3 issued in October, but the April 2016 release is scheduled for Friday, 18th March 2016. The last release of CTV3 will be published in April 2018.

How have CFS and related terms been listed within SNOMED CT and CTV3?


Prior to July 2015, all editions of SNOMED CT had the following listings for CFS, ME and PVFS:

Chronic fatigue syndrome (with ME – Myalgic encephalomyelitis and several other related and historical terms listed under Synonyms) was assigned two parent disorder classes: Mental disorder, and Multisystem disorder.

Postviral fatigue syndrome was listed under Children to Chronic fatigue syndrome.

Read Codes (CTV3)

The twice yearly Read Codes releases (April and October) are available only to license holders but the codes can be viewed through this public resource (caveat: it is unclear how often this NCBO BioPortal ontology resource is updated with new releases for individual ontology systems):

See: BioPortal Xa01F

For CTV3, Xa01F Chronic fatigue syndrome (with ME – Myalgic encephalomyelitis and PVFS – Postviral fatigue syndrome under Synonyms) is listed, hierarchically, under two parent disorder classes: as a Sub Class of both Neurasthenia, under parent: Mental health disorder, and as a Sub Class of Neurological disorder.


Mental health disorder > Neurotic disorder > Somatoform disorder > Neurasthenia > Chronic fatigue syndrome


Neurological disorder > Chronic fatigue syndrome

See also the Visualization tab for a diagrammatic representation of dual parentage:

Correspondence between Countess of Mar and UK Health and Social Care Information Centre

Forward-ME is an informal group for ME charities and voluntary organizations, chaired by the Countess of Mar, who also serves as Co-chair to the All-Party Parliamentary Group on Myalgic Encephalomyelitis (ME).

Between November 2014 and June 2015, Lady Mar was in correspondence with Mr Leon Liburd, Senior Support Analyst Systems and Service Delivery, and Ms Elaine Wooler, Advanced Clinical Terminology Specialist, UK Health and Social Care Information Centre.

Their correspondence (in reverse date order) was published on the Forward-ME website in June and can be read here Correspondence re SNOMED added June 2015

or open PDF here on Dx Revision Watch

Click link for PDF document  Correspondence re SNOMED

Changes to SNOMED CT

As a result of these exchanges, Lady Mar was advised that the relationship between the entry for 52702003 Chronic fatigue syndrome and the Mental disorder parent had been retired. In future editions, Chronic fatigue syndrome would be listed under the single parent, 281867008 Multisystem disorder.

See here

Additionally, 51771007 Postviral fatigue syndrome was being removed as a subtype of 52702003 Chronic fatigue syndrome (disorder) – though no rationale for this specific decision appears to be provided within the correspondence.

See here

[So 51771007 Postviral fatigue syndrome would be no longer be listed as a sub class under Children to 52702003 Chronic fatigue syndrome but directly under two parents: 281867008 Multisystem disorder and 123948009 Post-viral disorder.]

These changes were effected in the July 2015 release for the International Edition (Release 20150731).

They were subsequently incorporated into the September 2015 US Extension (Release 20150901), the October 2015 UK Extension (Release 20151001) and the November 2015 Swedish Extension (Release 20151130). It is expected that other country Extensions will also reflect these changes in their forthcoming releases.

Within the correspondence, on 11 November 2014, Mr Leon Liburd had also advised Lady Mar:

“It is also noted that the corresponding representation in the UK’s Clinical Terms Version 3 terminology product Xa01F | Chronic fatigue syndrome is classified as both a Neurological disorder and a Mental health disorder. As such, any conclusions emerging from the SNOMED CT discussions would also be reflected in the CTV3 UK product.”

Clarification re CFS and CTV3

In November, I contacted the UK Health and Social Care Information Centre for clarification of how CFS and its various Synonyms are currently listed within CTV3.

On 20 November, I was advised by Karim Nashar, Terminology Specialist, UK Terminology Centre, Health and Social Care Information Centre, that:

“[Xa01F | Chronic fatigue syndrome was being moved] under a single supertype 281867008 | Multisystem disorder (disorder) as to reflect the SNOMED correction in CTV3″

and that this change should be reflected in the April 2016 CTV3 release.

As noted above, Clinical Terms Version 3 (CTV3) is being deprecated and the last release of CTV3 will be published in April 2018.

The ICD-11 Beta draft and proposed classification of the G93.3 legacy terms

In June, WHO’s Dr Robert Jakob had told me that if TAG Neurology’s proposals and rationales for the G93.3 legacy terms were not ready for public release in September, he projected their release by December, latest (see towards end of Post #324).

No proposals were released in September and none in December. Eight years into the revision process and stakeholders still don’t know how ICD Revision proposes to classify the ICD-10 G93.3 legacy terms for ICD-11.

On 28 December, I called again, via the ICD-11 Beta Comments mechanism, for these terms to be restored to the public version of the Beta drafting platform.


1 UK Terminology Centre (UKTC):


3 NIB document ‘Personalised Health and Care 2020: A Framework for Action’:

4 IHTSDO browser:

5 Retirement of Read Version 2 and Clinical Terms Version 3:

6 NCBO BioPortal Read Codes (CTV3) Xa01F Chronic fatigue syndrome

7 Forward-ME Correspondence re SNOMED added June 2015



ICD-11 Mental Health TAG opposes inclusion of “Functional clinical forms of the nervous system” under neurological conditions

Post #318 Shortlink:

Update: In September, a series of ICD-11 Symposia were held at the World Psychiatric Association XVI World Congress, in Madrid. These included Symposium Code SY469: Proposals and evidence for the ICD-11 classification of dissociative disorders, the abstract for which can be found here (pages 354-355).

Update: For those registered for enhanced access to the public version of the ICD-11 Beta drafting platform, there are some recent proposals on behalf of Mental Health TAG for the Dissociative disorders block, here.


As previously posted:

In my September post, Briefing paper on ICD-11 and PVFS, ME and CFS: Part 2, I reported on a proposal by the ICD-11 Topic Advisory Group (TAG) for Neurology for the inclusion of a disorder group termed, “Functional clinical forms of the nervous system,” under Neurological conditions.

Under this new parent class, it has been proposed to locate a list of “functional disorders” (Functional paralysis or weakness; Functional sensory disorder; Functional movement disorder; Functional gait disorder; Functional cognitive disorder, Functional visual loss etc.).

In ICD-10, these conditions are accommodated under the Chapter V F44 Dissociative [conversion] disorders section.

In DSM-5, they are classified under “Conversion Disorder (Functional Neurological Symptom Disorder),” which is one of several categories that sit under the DSM-5 “Somatic Symptom and Related Disorders” section. They are cross-walked to ICD-10-CM’s F44.4 to F44.7 codes, depending on the symptom type.

The rationale for this proposed new parent class is set out in this recent paper by Stone et al:

Functional disorders in the Neurology section of ICD-11: A landmark opportunity

Jon Stone, FRCP, Mark Hallett, MD, Alan Carson, FRCPsych, Donna Bergen, MD and Raad Shakir, FRCP*

Neurology December 9, 2014 vol. 83 no. 24 2299-2301

doi: 10.1212/WNL.0000000000001063

Full free text

Full free PDF

*Raad Shakir chairs the Topic Advisory Group for Neurology

See also (full paper behind paywall):

Functional neurological disorders: The neurological assessment as treatment. Stone J. Neurophysiol Clin. 2014 Oct;44(4):363-73 Abstract:


Opposition from Mental Health TAG

If you are registered for increased access to the public version of the Beta drafting platform, you can read the response from Mental Health TAG, here.

If you are not registered, see below:

Proposal for Deletion of the Entity

Functional clinical forms of the nervous system

Proposal Status: Submitted


Definition does not exist for this content


This grouping should be deleted.

These are by definition not neurological conditions, as indicated by the phrase included in the definitions provided: ‘in which there is positive evidence of either internal inconsistency or incongruity with other neurological disorders’. If there is no evidence of a neurological mechanism or etiology, the rationale for including these in the classification of neurological disorders is unclear to say the least.

In contrast, these have always been viewed as mental disorders (from the days of Sigmund Freud), and there is no evidence about their etiology or mechanism that is inconsistent with that formulation.

Prior to ICD-10, these conditions were conceptualized as Conversion Disorders. This terms is considered obsolete because it refers to a psychodynamic mechanism that is theoretical and not ideally descriptive. ICD-10 offered a transitional title, calling them Dissociative [conversion] disorders.

For ICD-11, the proposals for Mental and Behavioural Disorders refer to these as Dissociative disorders, dropping the ‘Conversion’ part of the term. Dissociative disorders are defined descriptively, as ‘characterized by disruption or discontinuity in the normal integration of memories of the past, awareness of identity, immediate sensations, and control over bodily movements that are not better explained by another mental and behavioural disorder, are not due to the direct effects of a substance or medication, and are not due to a neurological condition, sleep-wake disorder, or other disorder or disease. This disruption or discontinuity may be complete, but is more commonly partial, and can vary from day to day or even from hour to hour.’ There is not basis for suggesting that this formulation is inconsistent with the phenomena proposed for inclusion here as ‘Functional clinical forms of the nervous system’.

The fact that neurologists may be asked to evaluate these conditions is not an adequate rationale for defining them as neurological disorders, nor are concerns about reimbursement policies that are unwisely based on divisions among specialists’ scope of practice based on ICD chapters.

The Mental Health TAG is aware that there is a vocal group of advocates for this terminology among neurologists. In fact, this terminology was included as alternate terminology in DSM-5. However, in DSM-5, these are still very clearly classified as Mental disorders.

Similarly, these terms can be added as inclusion terms to the equivalent categories in the Mental and behavioural disorders chapter.

In spite of its popularity among at least some neurologists, this terminology is currently viewed in psychiatry as obsolete, and based on a mind-body split (division between ‘organic’ and ‘non-organic’) we are elsewhere attempting to remove from the ICD-11. The implied contrast is between a ‘real’ (medical) disorder and a ‘functional’ (psychiatric) disorder.

A further problem with this terminology is its inconsistency with WHO’s official policy use of terminology related to ‘functioning’ (function, functional), as defined in the ICF.

In some instances of the use of the term ‘functional’ in other parts of proposals for ICD-11, it is not clear that the proposals use the term ‘functional’ in this same sense, or if they mean something close to ‘idiopathic’. However, it is quite clear that what is meant in this group of proposals is ‘without neurological explanation or plausible or demonstrable etiology’.

However, this terminology is in any case problematic. In addition to requesting that this group of categories be deleted from the classification and instead integrated appropriately as inclusion terms in the chapter on Mental and Behavioural Disorders, the Mental Health TAG requests that the Classifications Team examine other uses of the term ‘functional’ in proposals for ICD-11 and consider either appropriate parenting in Mental and behavioural disorders or alternative terminology.

The Mental Health TAG also requests that this issue be revised by the Revision Steering Group (and or Small Executive Group) in order to arrive at an ICD-wide solution as efficiently as possible. The Mental Health TAG requests that this issue not simply be arbitrated by the same TAGs that have made these proposals.

–On behalf of Mental Health TAG


There are no references attached for this proposal item

Comments on this proposal


The Mental Health TAG also requests that this issue be revised by the Revision Steering Group (and or Small Executive Group) in order to arrive at an ICD-wide solution as efficiently as possible. The Mental Health TAG requests that this issue not simply be arbitrated by the same TAGs that have made these proposals.

–On behalf of the Mental Health TAG
Geoffrey Reed 2015-Jan-10 – 23:10



An alternative could be that this grouping could be retained but with appropriate primary parenting to Dissociative disorders in the Mental and behavioural disorders chapter.

Entities of ‘functional clinical forms’ have already been proposed to be added in the appropriate categories in Dissociative disorders. Most of them are included in Dissociative motor disorder, though several are included in Dissociative disorder of sensation. One is included in dissociative amnesia.

However, the name of these entries – i.e., functional disorders – remains an issue as described above, which should be resolved at the ICD-wide level.

Note that if the solution selected involved retaining these categories, perhaps renamed, but primary parenting them appropriately in Dissociative disorders, it will be more appropriate to move the secondary parented categories to the main Disease of the nervous system chapter rather than listing them in clinical forms.

–On behalf of the Mental Health TAG
Geoffrey Reed 2015-Jan-12 – 09:14 UTC


I will update if further comment is uploaded on behalf of the Mental Health TAG, the Neurology TAG, ICD-11 Revision Steering Group, the WHO classification experts etc.


Note for stakeholders with an interest in the ICD-10 G93.3 categories: There is currently no inclusion within any chapter of the ICD-11 Beta draft for a specific parent class for “Functional somatic syndromes,” or “Functional somatic disorders” or “interface disorders” under which, conceivably, those who consider CFS, ME, IBS, FM et al to be speciality driven manifestations of a similar underlying functional disorder might be keen to see these terms aggregated.

On July 24, 2014, ICD Revision’s Dr Geoffrey Reed stated there has been no proposal and no intention to include ME or other conditions such as fibromyalgia or chronic fatigue syndrome in the classification of mental disorders.

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