Summary: ICD-11 Alpha Draft and iCAT (PVFS, ME and CFS)

Summary: ICD-11 Alpha Draft and iCAT (PVFS, ME and CFS)


Compiled by Suzy Chapman Dx Revision Watch

May be republished if published in full, unedited and with source acknowledged. 

A version of this report was published on Co-Cure on 11 June 2010.

The information in this summary relates to proposals for ICD-11. It does not apply to ICD-10-CM, the forthcoming US “Clinical Modification” of ICD-10, scheduled for implementation in October 2013.

This report provides a summary of the material published on Dx Revision Watch site on 7 June that included screenshots from the iCAT, the wiki-like collaborative authoring platform through which ICD-11 is being drafted.


To view proposals as they currently stand, see the 12 screenshots here:

PVFS, ME, CFS: the ICD-11 Alpha Draft and iCAT Collaborative Authoring Platform, 7 June 2010, Post # 46:


Presentation of an alpha draft to the WHA:

A hard copy “snapshot” of the ICD-11 alpha draft, as it stood at that point, was presented by WHO at the 63rd World Health Assembly meeting, between 17 and 25 May.

According to page 38 of the document “ICD-11 Revision Project Plan”:

“WHO will consider endorsement of the alpha draft, after all concerns of RSG and the Classification TAGs have been duly taken into account. The alpha draft is a frozen state of development of the ICD-11 that will include a large part of the structural changes, and the majority of the definitions. The Alpha draft will be produced in a traditional print and electronic format. The Alpha Draft will also include a Volume 2 containing the traditional sections and including a section about the new features of ICD-11 in line with the style guide. An index for print will be available in format of sample pages. A fully searchable electronic index using some of the ontological features will demonstrate the power of the new ICD” [1].

The date by which WHO anticipates this stage should be reached is unconfirmed.


For better understanding, it is important that the brief iCAT Glossary page is read in conjunction with the iCAT screenshots, especially the Glossary entries for ICD-10 Code, ICD Title, Definition, and for the Terms: Synonyms, Inclusions and Exclusions [2].

Read the iCAT Glossary here:

Secondly, it needs to be understood that the alpha draft is a “work in progress”. Not all content will have been compiled yet and entered into the iCAT and there are many blank fields awaiting population for all chapters and all categories. It also needs to be understood that some text already entered into the various “Details” fields may still be in the process of internal review.


In ICD-10, there is no textual content for the three terms “Postviral fatigue syndrome”, “Benign myalgic encephalomyelitis” and “Chronic fatigue syndrome” .

There are no definitions and the relationship between the three terms is not specified.

In ICD-11, categories will be defined through the use of multiple parameters: Title & Definition, Terms: Synonyms, Inclusions, Exclusions, Clinical Description, Signs and Symptoms, Diagnostic Criteria and so on, according to a common “Content Model” [3].

The level of detail currently visible in the iCAT isn’t sufficiently specific to enable me to present an unequivocal overview of current proposals for potential changes to hierarchy or for the specification of the relationships between the three terms of interest to us.

Based only on the information visible in the iCAT as it stood at 11 June 2010, it appears that instead of:

ICD-10: Volume 1: The Tabular List (version for 2007)

Chapter VI (6)

Diseases of the nervous system


Other disorders of the nervous system


G93 Other disorders of brain


G93.3 Postviral fatigue syndrome
Benign myalgic encephalomyelitis

(with Chronic fatigue syndrome indexed to G93.3 in ICD-10: Volume 3: The Alphabetical Index)

what appears to be being proposed at this point for ICD-11 is that:

The classifications coded between G83.9 thru G99.8 in ICD-10 Chapter VI: Diseases of the nervous system, are being reorganised.

For ICD-11, Chapter 6, codings beyond G83.9 are represented by new parent classes numbered GA thru to GN;


Chapter 6 VI Disorders of the nervous system

G80-G83 Cerebral palsy and other paralytic syndromes
GA Infections of the nervous system
GB Movement disorders and degenerative disorders
GC Dementias
GD Epilepsy and seizures
GN Other disorders of the nervous system

“GN Other disorders of the nervous system” is parent to five child classes which have been assigned the “Sorting labels” Gj90-Gj94.

(A Sorting label is a string that can be used to sort the children of a category. This is not the ICD code.)

Four of these five Gj9x classes have a complex hierarchy of child and grandchildren classes.

At Gj92, sits “Chronic fatigue syndrome”

“Gj92 Chronic fatigue syndrome” has no child classes of its own.

Next to “Gj92 Chronic fatigue syndrome” is an icon for “Category Notes and Discussions”.

There is one Category Note for Gj92 which records:

“[Reason for change]: Change in hierarchy for class: G93.3 Postviral fatigue syndrome. Parents added: (Gj90-Gj99 Other disorders of the nervous system). Parents removed: (G93 Other disorders of brain). New hierarchy”

(Note that the removal of the parent category “G93 Other disorders of brain” will affect a large number of categories classified under G93 in ICD-10, not just those at G93.3.)

In the iCAT production server, click on “Gj92 Chronic fatigue syndrome” and “Details for Gj92 Chronic fatigue syndrome” will display on the right of your screen (it may take a few seconds for the text to load). Or you can view the screenshots on my site:

“Gj92 Chronic fatigue syndrome” is an ICD Title term with a Details page, a Definition and an Inclusions term (but with no Synonyms, Exclusions or other fields yet populated).

“Benign myalgic encephalomyelitis” is listed under Inclusions (the relationship is not currently specified, eg “Synonym” or “Subclass” or whatever).

Extract: iCAT Glossary

“Inclusion terms appear in the tabular list of the traditional print version and show users that entities are included in the relevant concept. All of the ICD-10 inclusion terms have been imported and accessible in the iCat. These are either synonyms of the category titles or subclasses which are not represented in the classification hierarchy. Since we have synonyms as a separate entity in our ICD-11 content model, the new synonyms suggested by the users should go into the synonyms section. In the future, iCat will provide a mechanism to identify whether an inclusion is a synonym or a subclass.”


In the iCAT ICD Categories list, there is no Gj9x Sorting label listing for “Postviral fatigue syndrome” or “Benign myalgic encephalomyelitis” under “GN Other disorders of the nervous system” or under any other parent or child class, and consequently no Category Details display for either term.

(Whether this is because Inclusion terms would appear in the tabular list version but not in the iCAT version or whether this is because of proposed changes to the hierarchy and/or relationship between the three terms, cannot be determined from the information as it stands at 11 June.)

“Postviral fatigue syndrome” is not currently specified under Inclusions in “Details for Gj92 Chronic fatigue syndrome”.

Again, whether this is because “Postviral fatigue syndrome” would be accounted for in the tabular list version or whether this is because it may be being proposed that the term “Postviral fatigue syndrome” (which has lost its parent class “G93 Other disorders of brain”) should be subsumed into “Chronic fatigue syndrome”, with “Chronic fatigue syndrome” as the new ICD category Title, cannot be determined from the information as it currently stands.


If you pull up the iCAT Details for ICD-11 Chapter 5: F48.0 Neurasthenia (or view the screenshots on my site)

“postviral fatigue syndrome” is listed under Exclusions to Neurasthenia and is referenced thus:

“postviral fatigue syndrome”    G93.3 -> Gj92 Chronic fatigue syndrome

In iCAT Chapter 18: R53 Malaise and Fatigue

“fatigue syndrome postviral” [sic] is also listed under Exclusions, referenced

G93.3 -> Gj92 Chronic fatigue syndrome

But that in the absence of further information, it is currently unclear what the proposed hierarchical status of Postviral fatigue syndrome will be in relation to Chronic fatigue syndrome.


When you click on the Category Notes icons for some other categories, the Notes are often more explicit, for example, the Category Note for:

GN Other disorders of the nervous system

> Gj90 Disorders of CSF pressure and flow
         > Gj90.0 Increased intracranial pressure disorders

Reads: [Reason for change]: Create class with name: Increased intracranial pressure disorders, parents: Disorders of CSF Pressure and Flow

replaces G93.5, G93.6, and G93.7

The Category Note for “Gj90 Disorders of CSF pressure and flow” records that this class has been created to replace:

G91, G92, G93.0, G93.2, G94.0, G94.1, G94.2, G96.0, G97.0, G97.1, G97.2

(which also gives an idea of the extent to which the structure of ICD-10 classifications between G90 – G99.8 is being reorganised.)

In the absence of an Alpha Draft, I shall be contacting the chair of the Topic Advisory Group for Neurology for further clarification.


So what can be said is that currently in the iCAT for ICD-11 drafting:

That under Chapter 6 (Neurology):

The parent class “G93 Other disorders of brain” is removed.

“Chronic fatigue syndrome” displays as a Title term in the Categories list.

It is a child to parent class “GN Other disorders of the nervous system”.

It has been assigned the “Sorting label” Gj92.

“Gj92 Chronic fatigue syndrome” has a Definition field populated.

It has an External Definitions field populated which includes definitions imported from other classification systems, the text of which includes “Also known as myalgic encephalomyelitis”.

It has “Benign myalgic encephalomyelitis” specified under Inclusions.

It has no Synonyms, Exclusions or other descriptor fields populated yet.

That at this point and as far as the iCAT version is concerned, neither “Postviral fatigue syndrome” nor “Benign myalgic encephalomyelitis” have been listed as ICD Title terms under the parent class “GN Other disorders of the nervous system” or under any other class.

That at this point and as far as the iCAT version is concerned, there is no accounting for “Postviral fatigue syndrome”, other than that “Postviral fatigue syndrome” is specified under Exclusions to Chapter 5 F48.0 Neurasthenia and to Chapter 18 R53 Malaise and fatigue and is referenced as

“postviral fatigue syndrome” G93.3 -> Gj92 Chronic fatigue syndrome


So please read the iCAT Glossary of Terms page, have a look at the screenshots and then have a poke around in the iCAT – you can’t break anything as members of the public have no editing rights [4].

I shall continue to monitor the iCAT production server closely and report on any changes to proposals for Category listings and on the progress of the population of content. (There has been no change since this report was compiled.)

And if you were thinking of getting a G93.3 tattoo done – well it might be best to hang on for a bit…


[1] ICD-11 Revision Project Plan – Draft 2.0 (v March 10)
Describes the ICD revision process as an overall project plan in terms of goals, key streams of work, activities, products, and key participants:

[2] iCAT Glossary

[3] Content Model Specifications and User Guide (v April 10)
Identifies the basic properties needed to define any ICD concept (unit, entity or category) through the use of multiple parameters:

[4] iCAT production server and Demo and Training iCAT Platform:
iCAT production server:
Demo and Training iCAT Platform: /

Compiled by Suzy Chapman