About the International Consensus Criteria (ICC) & Primer for ME

Overview of the International Consensus Criteria & Primer for Myalgic Encephalomyelitis (ME)

 

 

‘The failure to agree on firm diagnostic criteria has distorted the data base for epidemiological & other research, thus denying recognition of the unique epidemiological pattern of Myalgic Encephalomyelitis.’

~ Dr. A. Melvin Ramsay ~

 

 

Image by JS based on the ICC

The Problem

Overly inclusive diagnostic criteria has led to widespread misperceptions about Myalgic Encephalomyelitis (ME). These misperceptions have fostered cynicism and have had a significant negative impact on how ME is viewed by the medical community, patients, families, and the general public.

ME is largely absent from medical school curricula. As a result, major scientific advances, along with appropriate diagnostic and treatment protocols, have not reached many busy medical practitioners.

Most doctors remain unaware of the complexity, severity, and multi-system nature of ME. Consequently:

• Patients may go undiagnosed or misdiagnosed

• Patients may receive inappropriate or no treatment

• Patients may be shunned, gaslighted, or socially isolated

This lack of understanding perpetuates harm and delays meaningful care.

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A Possible Solution

Adoption of the International Consensus Criteria (ICC) and International Consensus Primer (ICP) for Myalgic Encephalomyelitis (ME)

In regions where national health agencies have not developed clinical guidelines for Myalgic Encephalomyelitis, or where existing guidelines have not been formally adopted, the International Consensus Criteria (ICC) provide one of the most robust, evidence-based frameworks available.

Developed by international experts in ME, the ICC offer clear, biologically grounded diagnostic criteria that help healthcare professionals, educators, policymakers, and support services to accurately recognise, diagnose, and support people with ME. 

By focusing on core pathophysiological features of the disease, the ICC help reduce misdiagnosis, improve clinical consistency, and promote a more accurate understanding of ME as a serious, multi-system neurological illness.

When used alongside the International Consensus Primer (ICP), the ICC equip clinicians with practical tools to guide assessment, management, and patient support, particularly in settings where formal guidance is absent or insufficient.

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About the International Consensus Criteria (ICC)

In 2011, a group of internationally recognized ME experts, including Ireland’s Professor Austin Darragh and clinicians such as Dr. Nigel Speight, collaborated to develop the International Consensus Criteria (ME-ICC).

The ME-ICC reconceptualizes ME as an acquired neurological disease characterized by complex, global dysfunctions. Notably, it removes “fatigue” as a defining symptom.

Instead, the ME-ICC identifies specific and essential symptom domains, including:

• Post-Exertional Neuroimmune Exhaustion (PENE)

• Neurological impairments

• Immune, gastrointestinal, and genitourinary impairments

• Energy metabolism and transport impairments

By clearly defining ME based on underlying pathophysiology rather than nonspecific fatigue, the ICC provides a more accurate framework for diagnosis, research, and patient care.

The International Consensus Primer (ICP)

Published in 2012 following the release of the International Consensus Criteria (ICC) in 2011, the International Consensus Primer (ICP) was developed to provide clinicians with a clear, practical, and user-friendly reference for recognising, diagnosing and managing ME.

The ICP includes:

• A concise summary of current pathophysiological findings underpinning the ICC

• A comprehensive clinical assessment and diagnostic worksheet to support consistent diagnosis of both adult and paediatric patients worldwide

• Treatment and management guidelines offering a blueprint for personalized, holistic patient care, including both non-pharmaceutical and pharmaceutical approaches

• Patient self-help strategies addressing energy conservation, diet, and daily management

• Educational considerations specific to children with ME

The ICP is designed primarily for primary care clinicians and specialists in internal medicine, though other healthcare practitioners may also find it valuable.

Medical school faculties are strongly encouraged to include the ICP in their curricula to ensure future clinicians are equipped with evidence-based knowledge of ME.

The International Consensus Primer represents the collective expertise of an international panel of clinicians and researchers, reflecting insights gained through extensive research and hundreds of thousands of hours of clinical investigation into this complex disease.

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Suggestion re the label/name

'Myalgic Encephalomyelitis, a name that originated in the 1950s, is the most accurate and appropriate name because it reflects the underlying multi-system pathophysiology of the disease. 

Our panel strongly recommends that only the name ‘myalgic encephalomyelitis’ be used to identify patients meeting the ICC because a distinctive disease entity should have one name. 

Patients diagnosed using broader or other criteria for CFS or its hybrids (Oxford, Reeves, London, Fukuda, CCC, etc.) should be reassessed with the ICC. 

Those who fulfill the criteria have ME; those who do not would remain in the more encompassing CFS classification.'

~ pg ii, 1. ICP 2012

Suggestion re the criteria and how to solve the 'soup' that we recognise which has led to so many problems, i.e., the soup that includes fatiguing conditions, depression, Fibromyalgia and CFS

'Remove patients who satisfy the ICC from the broader category of CFS. The purpose of diagnosis is to provide clarity. The criterial symptoms, such as the distinctive abnormal responses to exertion can differentiate ME patients from those who are depressed or have other fatiguing conditions. Not only is it common sense to extricate ME patients from the assortment of conditions assembled under the CFS umbrella, it is compliant with the WHO classification rule that a disease cannot be classified under more than one rubric. 

The panel is not dismissing the broad components of fatiguing illnesses, but rather the ICC are a refinement of patient stratification. As other identifiable patient sets are identified and supported by research, they would then be removed from the broad CFS/CF category.' 

~ Pg ii, 2. ICP 2012

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Image by JS based on the ICC

The International Consensus Criteria (2011) along with the Primer (2012) can be used to support recognition, diagnosis & management of Myalgic Encephalomyelitis (ME). It can also be used to educate and inform medics and others about this illness. Medics such as GPs and specialists can follow the International Consensus Primer (ICP) to definitively diagnose ME and pursue symptom treatments to help improve quality of life.

Both criteria and primer were specifically written about and for ME, designed to assess the unique combination of symptoms found in ME.

Links to those documents below: -

International Consensus Criteria

International Consensus Primer

 

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Image by JS based on the ICC

The ICC alone is not sufficient to confirm an ME diagnosis. A thorough clinical evaluation is required to firmly establish the diagnosis and to rule out other conditions. The International Consensus Primer (ICP) supports this next step by guiding clinicians through recognition, diagnosis, differential diagnosis, and appropriate management.

Developed by ME experts, the ICP is a practical physician guide for assessing and treating patients who meet the ICC. It highlights key clinical features such as immune dysfunction, neurological impairments, and cardiac abnormalities that are frequently overlooked in other guidance.

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Image by JS based on the ICC

 

 

Interpretation of the International Consensus Criteria (ICC)

Lily Silver, a person who lived with ME, left a great legacy - a treasure trove of information and advice for people with ME via her page The Sleepy Girl Guide To Social Security Disability and the How To Get On website for people in the US, also useful for people elsewhere.

Lily's interpretation of the International Consensus Criteria (ICC 2011), 'How Do I Know If I Have ME is particularly good and quite useful; the page includes a simple explanation about ME and PENE. It goes through the lCC, providing a more simple explanation on what it is about. Please see that interpretation here.

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Image by JS based on the ICC

Symptom & Severity & Post Exertion Response Questionnaires

De Paul Questionnaires

We suggest that alongside the use of the ICP that clinicians and patients use the De Paul Symptom and Severity Questionnaire (DSQ-2) as well as the De Paul PEM Questionnaire to evidence symptoms and severity, and the post exertion response.

 

There are also specific paediatric questionnaires available which include both parent and child forms, i.e. the DSQ-PED Parent and Child Forms.

 

See all questionnaires below via the link below.

De Paul Questionnaires

 

 

     ME Advocacy .Org's 'Do I Fit the ICC Criteria Questionnaire' 

     Do I Fit the ICC? is an easy-to-use questionnaire based on the ICC written by meadvocacy.org . It is helpful because of its simlicity; the ICC can be difficult to absorb because it uses a lot of scientific and medical language.

Do I Fit the ICC?

     Web Form Questionnaire

     The web form questionnaire from the Swiss Society for ME & CFS (SGME) is based on the ICC to help individuals with ME communicate with their doctor, i.e., to help them understand the reality of their Myalgic Encephalomyelitis. This online questionnaire enables a patient to determine whether the diagnosis of ME according to the ICC may be applicable to them.  Upon completion of the form there is an option to print it out to give to the doctor.

     Please access that online form here

 

Image by JS based on the ICC

 Functional Capacity/Disability Tools

• FUNCAP
• Bells Disability Scale

The FUNCAP Questionnaire is a tool designed to communicate functional capacity and capture symptom exacerbation resulting from everyday activities. FUNCAP was developed through multiple rounds of surveys and feedback from thousands of people with ME. It is designed to assess post-exertional symptom response and functional capacity, and can be used in the investigation of a possible ME diagnosis, clinical follow-up, disability benefit applications, and research as an outcome measure.

It is available in two versions: a longer form with 55 questions FUNCAP 55 and a shorter form with 27 questions FUNCAP 27

Bells Disability Scale is a scale for the classification of disability in ME. It was developed in 1995 by David Bell M.D. specifically for ME.

Bells scale has been tried and tested for decades, but the creator was already aware that it is subject to certain limitations. It is not possible for all patients to clearly rank themselves on the Bell scale, for example, because they achieve a score of 50 in one area but only a score of 30 in another. In this case, a doctor or a relative can help with an overall assessment.

Classification on the Bells scale is also complicated by the fact that the symptoms of ME fluctuate due to various factors. The score awarded should be closest to the overall degree of restriction over a longer period of time.

Bells Disability Scale

 

Image by JS based on the ICC

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Lily Silver was an advocate for people with Myalgic Encephalomyelitis (ME). She created resources such as the How to Get On website and the Sleepy Girl Guide to Social Security Disability to support homebound or severely affected patients. 

We remember Lily Silver, ME Patient & Advocate

Disclaimer: The information in this post is for general information purposes only. While we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the post or the information, products, services, etc contained in the post for any purpose. Any reliance you place on such information is therefore strictly at your own risk.The suitability of any solution is totally dependent on the individual. It is strongly recommended to seek professional advice and assistance.