PVFS, ME and CFS in classification and terminology systems: notes for the future

Post #355 Shortlink: https://wp.me/pKrrB-4Yv

In 2002, I set up FreeMEuk — a Yahoo Group support and information exchange for patients with ME, CFS, and for carers, like myself. In 2007, I launched ME agenda to provide patients, carers and advocates with information, resources and commentary on the political issues affecting the lives of myalgic encephalomyelitis (ME) patients in the UK.

In January 2010, I created this site specifically to monitor and report on the development of the American Psychiatric Association’s DSM-5, the development of the World Health Organization’s ICD-11 and on other classification and terminology systems. Where appropriate, I have galvanized stakeholders to participate in review and comment exercises or co-ordinated other forms of response.

Down the years, I’ve undertaken numerous short and long-term ad hoc projects, advised others on technical matters relating to classification and terminology systems, submitted and collaborated in the submission of proposals, briefed politicians and patient organizations and kept patient forums up to date with key developments.

Today I am retiring after 17 years of advocacy work.

My sites will remain online for the foreseeable future. Over the coming months I shall be carrying out some housekeeping on this site to remove or archive older, less relevant content.

Classification and terminology systems are going to need continued monitoring; where required, input from stakeholder groups — clinicians, researchers, health practitioners and professional body allies, social workers, disability lawyers and advocacy organizations will need to be co-ordinated.

Where no process for public stakeholder input currently exists, channels of direct communication will need to be opened with the agencies responsible for the development and management of these systems and collaborative dialogues established.

WHO, for example, ostensibly gives more consideration to evidence based submissions supported by rationales, international consensus and input from clinical and professional bodies — has scant regard for patient opinion and none whatsoever for petitions or mass mailings — the latter and similar types of “action” will only undermine the careful work and discourse that I and others have fostered.

All these systems will require regular monitoring:



DSM-5 published in May 2013; it has an update process which reviews formal submissions for changes to criteria, related texts, assessment measures or corrections. DSM-5 also absorbs relevant coding changes in the annual FY releases of the U.S. specific ICD-10-CM. Approved proposals are posted for a 45 day stakeholder comment period. For example, in 2015, an edit in the text for Somatic symptom disorder¹ was approved for implementation and the revised text published in the DSM-5 Update Supplement.




Member states using the WHO’s ICD-10 don’t all use the same version (or the most recent version), for example, NHS England currently mandates the use of ICD-10 Version: 2015, not Version: 2016. WHO has said that the final update to ICD-10 will be Version: 2019. This final release is understood to have been prepared but is not currently available on the ICD-10 Browser platform.



The U.S. uses ICD-10 for reporting mortality and developed a “clinical modification” of ICD-10 (called ICD-10-CM) for morbidity. A new release of ICD-10-CM is posted on the CDC website annually, in June.

There are two public NCHS/CDC Coordination and Maintenance Committee meetings a year through which proposals for changes to the ICD-10-CM can be submitted for discussion (in March and September) followed by a stakeholder comment period.

At the September 12, 2018 C & M Committee meeting, proposals for changes to the existing coding of R53.82 Chronic fatigue syndrome NOS; G93.3 Postviral fatigue syndrome, Benign myalgic encephalomyelitis; and a second option for addition of the SEID term were presented for consideration and public comment¹. Whilst no changes for these codes were approved for implementation in the FY 2020 ICD-10-CM release, this topic will need continued monitoring as it may be revisited at a future C & M Committee meeting for presentation of revised proposals.

1 ICD-10-CM Coordination and Maintenance Committee Meeting, September 11-12, 2018, Diagnosis Agenda Part 2

Other country specific clinical modifications of ICD-10:

Around 25 member states are also using a modification of the WHO’s ICD-10. For example: Canada (ICD-10-CA); Germany (ICD-10-GM); Australia (ICD-10-AM). Belgium, Luxembourg and Spain use ICD-10-CM; Ireland and Slovenia use ICD-10-AM.

Countries using modifications of ICD-10 have individual update cycles and varying policies around public stakeholder input and review. Some countries post their Tabular List and Index modifications in the public domain; others are available only under licence, for example, Australia’s ICD-10-AM isn’t publicly available. The coding, hierarchy and chapter location of the PVFS, BME and CFS terms differs between some of the clinical modifications, while others remain consistent with the structure of the WHO’s ICD-10.

This table from the eHealth DSI Semantic Knowledge Base project compiles information provided from a number of member states on their use of ICD (or a modification of ICD) and their plans regarding potential future implementation of ICD-11. Information has been provided by: Austria, Belgium, Croatia, Cyprus, Czech Republic, Estonia, France, Germany, Greece, Hungary, Ireland, Italy, Luxenbourg, Malta, Netherlands, Portugal, Slovenia and Spain: Current status of the use of ICD by eHDSI deploying countries (2018)



SNOMED CT is a comprehensive clinical terminology system used in electronic patient health records. SNOMED CT maps to ICD-10 and there is a SNOMED CT to ICD-11 Mapping Project in progress.

SNOMED International has thirty-nine member countries. There is a SNOMED CT International Edition, for which two releases are issued per year (in January and July). There are a number of country specific national editions which release twice yearly updates on a staggered schedule. 12 of these national editions can be viewed on the SNOMED CT Browser platform.

SNOMED CT national editions absorb the changes in the most recent release of the International Edition but they can also include additional country specific terms. For example, the UK Edition has a unique Concept term: Medically unexplained symptoms (SCTID: 887761000000101). Prior to March 2019, the SNOMED CT Netherlands Edition had retained the term “neurasthenie” under Synonyms to Chronic fatigue syndrome, although the Concept term: Neurasthenia (SCTID: 268631001) and some associated codes had been retired from the International Edition and from all other national editions, some years ago. Following a request supported by a rationale, the term “neurasthenie” has now been removed from the Netherlands Edition.

The SNOMED CT Concept term for Chronic fatigue syndrome is SCTID 52702003 Chronic fatigue syndrome (disorder). Benign myalgic encephalomyelitis; and Myalgic encephalomyelitis are included as Synonym terms.

Following a successful submission in February 2018 for the addition of a new parent, SCTID: 52702003 Chronic fatigue syndrome (disorder) has been assigned under parent: SCTID: 118940003 Disorder of nervous system (disorder) since the July 2018 release of the SNOMED CT International Edition. This change of parent has been incorporated into the national editions.

The International Edition and the national editions of SNOMED CT will need monitoring twice yearly for changes and additions to their content.



On May 25, 2019, the 72nd World Health Assembly voted unanimously to adopt the ICD-11. The earliest date from which member states can start using the ICD-11 code sets for reporting data is January 1, 2022. Countries are beginning to evaluate the new edition and develop road maps but even early implementers are anticipated to take several years to prepare their health systems for migration. There is no mandatory implementation date and countries will transition to ICD-11 at their own pace and according to their resources and requirements. For some years to come, WHO will be accepting data reported using both ICD-10 and ICD-11 code sets.

ICD-11 update and maintenance: The current release of ICD-11 (Version 04/2019) on the Blue ICD-11 MMS platform is a stable release but an update and maintenance cycle is already in place.

The various ICD-11 Topic Advisory Groups and sub working groups, the Revision Steering Group and the Joint Task Force have all been sunsetted. WHO is now advised on how to process proposals for changes to ICD-11 by the Family of International Classifications Network (WHO-FIC); the Classifications and Statistics Advisory Committee (CSAC); the Medical and Scientific Advisory Committee (MSAC); the Mortality and Morbidity Reference Groups; and the Functioning and Disability Reference Group.

Updates that impact on international reporting (the 4 and 5-digit structure of the stem codes) will be published every five years. Updates at a more detailed level can be published at annual rates. Additions to the ICD-11 index can be done on an ongoing basis. (There are currently in the region of 1200 unprocessed proposals waiting to be processed, with new proposals being submitted daily by WHO, professional bodies and other stakeholders.)

PVFS, BME, CFS: In a decision supported by the MSAC and CSAC committees, WHO rightly rejected the proposal of Dr Tarun Dua/Topic Advisory Group Neurology to delete the G93.3 legacy terms from the Diseases of the nervous system chapter and reclassify these terms in the Symptoms, signs chapter, under Symptoms, signs or clinical findings of the musculoskeletal system.

All three terms have been retained under their legacy chapter, under parent class: Other disorders of the nervous system, with 8E49 Postviral fatigue syndrome retained as the Concept Title. Benign myalgic encephalomyelitis; and chronic fatigue syndrome are both specified as Inclusion terms. Reciprocal exclusions for MG22 Fatigue were submitted for and approved.

The Proposal Mechanism platform for ICD-11 will need constant surveillance: there are currently no unprocessed proposals pending review for PVFS, BME and CFS. To date, WHO has rejected proposals for deprecation of the word “Benign” from Benign myalgic encephalomyelitis. This will need pursuing.


BDD: A proposal submitted by a third party in April 2017 for Deletion of 6C20 Bodily distress disorder has remained under review with the CSAC committee. According to WHO admins, in June 2019: “This proposal is being sent to MSAC to ensure the precedent decision on this issue still stands. Team3 WHO 2019-Jun-12 – 16:40 UTC”

(In February 2019, my own recommendations for 6C20 Bodily distress disorder had been marked as rejected by a different WHO admin team, with the comment: “This proposal has been extensively discussed by WHO and its advisory committees. There is no new scientific evidence to support this proposal and it will not be further processed. Team 2 WHO 2019-Feb-26 – 23:04 UTC)

I have requested that in any ongoing CSAC/MSAC deliberations in relation to the Bodily distress disorder category that these previously rejected recommendations are reviewed and reconsidered, including submissions for exclusions for PVFS, BME and CFS under 6C20 Bodily distress disorder.

See: Table: Status of ICD-11 processed proposals, Suzy Chapman, April 2019, for more information on approved and rejected proposals.


Clinical modifications of ICD-11:

It is understood that WHO’s intention is to limit development of national modifications and that policies around the licensing of ICD-11 are still being formulated. Countries developing modifications of ICD-11 will need surveillance.

See post World Health Assembly adopts ICD-11: When will member states start using the new edition? for more information on country plans.

See Presentation slides #36-38 for more information on licensing and the development of country modifications: Insights into the Next Revision: Like Texas, Everything is Bigger in ICD-11, Kathy Giannangelo, RHIA, CCS, CPHIMS, FHIMA, Texas Health Information Management Association.


ICD-11 and the CDDG guideline for mental disorders:

For ICD-11, the WHO Department of Mental Health and Substance Abuse has developed the “Clinical Descriptions and Diagnostic Guidelines (CDDG) for ICD‐11 Mental, Behavioural and Neurodevelopmental Disorders” (an equivalent publication to ICD-10’s “Blue Book”).

The CDDG provides expanded clinical descriptions, essential (required) features, boundaries with other disorders and normality, differential diagnoses, additional features, culture-related features and codes for all mental and behavioural disorders commonly encountered in clinical psychiatry; it is intended for mental health professionals and for general clinical, educational and service use.

WHO has said it plans to release the CDDG “as soon as possible” after WHA’s adoption of ICD-11. But it remains unclear whether the CDDG has been finalized or if it will be released this month, later this year or next year. See this post Clinical Descriptions and Diagnostic Guidelines (CDDG) for ICD‐11 Mental, Behavioural and Neurodevelopmental Disorders for more information.

Whilst clinicians have been able to register to review and provide feedback, no draft texts for the CDDG have been made available for public stakeholder scrutiny and comment and I have not had access, for example, to the most recent draft for the clinical descriptions and diagnostic guidelines for ICD-11’s Bodily distress disorder.


ICD-11 and the ICD-11 PHC:

Also under development is the WHO’s ICD-11 PHC — a clinical guideline written in simpler language to assist non-mental health specialists, especially primary care practitioners and non medically trained health workers, and also intended for use in low resource settings and low- to middle-income countries, with the diagnosis and management of common mental disorders. It comprises 27 mental disorders and contains no other disorders or diseases. Like the ICD-10 PHC (1996), this revised diagnostic and management guideline will not be a mandatory classification for member states.

For the mandatory core ICD-11 classification, WHO is going forward with the SSD-like Bodily distress disorder (BDD).

But the ICD-11 PHC is proposed to include a disorder category called “Bodily Stress Syndrome (BSS)” that has been adapted from the Fink et al (2010) Bodily distress syndrome (BDS). See Comparison of SSD, BDD, BDS, BSS in classification systems, July 2018.

Under exclusions and differential diagnoses for BSS, certain psychiatric and general medical diagnoses have to be excluded but CFS, ME; IBS; and FM appear not to be specified as exclusions. See this post Clinical Descriptions and Diagnostic Guidelines (CDDG) for ICD‐11 Mental, Behavioural and Neurodevelopmental Disorders for more information.

It’s not known when this guideline is expected to be finalized and made available for download. The ICD-11 PHC has not been developed on a publicly accessible platform and draft texts are not available for public stakeholder review and comment. This non mandatory 27 mental disorder guideline needs close scrutiny.



The WONCA developed and WHO endorsed, International Classification of Primary Care (ICPC-2) is under revision for ICPC-3.

ICPC-2 is available in 34 countries; used in primary care in 27 countries and is mandatory in 6 EU countries, eg the Netherlands. The content of ICPC-3 will be linked to relevant classifications, such as ICD-10, ICD-11, ICF, ICHI, DSM-5, clinical terminologies such as SNOMED-CT, but also to previous versions of ICPC.

The draft content for ICPC-3 is not being developed on a publicly accessible platform and it’s unclear whether any form of stakeholder review will be undertaken or at what point.

Caveat: This ICPC-3 roadmap on an ICPC-3 Working Group platform may have been revised since it was posted: ICPC-3 Roadmap Milestones August 28, 2018.

Dr Marianne Rosendal (Aarhus University), who has published with Prof Per Fink, is the European representative on WONCA’s International Classification Committee and a member of the revision committee for ICPC-2, as is the U.S.’s, Dr Michael Klinkman. ICPC-2 meeting summary documents dating from 2010/2011 indicate that Dr Rosendal has discussed the potential for inclusion of a Bodily distress syndrome or similar disorder concept in the ICPC-3. Prof Per Fink is likely to be lobbying hard for its inclusion. The development of ICPC-3 will need very close monitoring.



Comparison of Classification and Terminology Systems, Chapman & Dimmock, July 2018

Comparison of SSD, BDD, BDS, BSS in classification systems, Chapman & Dimmock, July 2018

Post: ICD-11 implementation package, June 06, 2019

Post: World Health Assembly adopts ICD-11: When will member states start using the new edition? June 17, 2019

Post: Clinical Descriptions and Diagnostic Guidelines (CDDG) for ICD‐11 Mental, Behavioural and Neurodevelopmental Disorders, June 28, 2019

Insights into the Next Revision: Like Texas, Everything is Bigger in ICD-11, Kathy Giannangelo, RHIA, CCS, CPHIMS, FHIMA, Texas Health Information Management Association

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

Post #327 Shortlink: http://wp.me/pKrrB-4aD

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.

See: http://purl.bioontology.org/ontology/RCD/Xa01F

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): http://systems.hscic.gov.uk/data/uktc/

2 SNOMED CT: http://systems.hscic.gov.uk/data/uktc/snomed

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

4 IHTSDO browser: http://browser.ihtsdotools.org

5 Retirement of Read Version 2 and Clinical Terms Version 3: http://systems.hscic.gov.uk/data/uktc/readcodes

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

7 Forward-ME Correspondence re SNOMED added June 2015


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