Definitions of myalgic encephalomyelitis and chronic fatigue syndrome

Over the course of three decades, many definitions or case criteria have been developed to diagnose either myalgic encephalomyelitis (ME), chronic fatigue syndrome (CFS), or systemic exertion intolerance disease (SEID). Some of these definitions or criteria are meant only to be diagnostic, i.e., used in a clinical setting to aid in diagnosis and some are meant to be used both in a clinical and research setting.

Each of these criteria and case definitions have been considered lacking in complete reliability and accuracy. Another change in the definition is assumed when medical research uncovers more of the pathophysiology of this illness.

ME

 * 1986 Ramsay definition
 * 2007 Nightingale definition
 * 2011 International Consensus Criteria (ICC)
 * 2014 London criteria

The International Consensus Criteria is currently used in some research and by few clinicians in some countries. Ramsay definition, Nightingale definition and London criteria are currently not in use.

CFS

 * 1988 CDC case definition ("Holmes criteria")
 * 1991 Oxford criteria*
 * 1994 CDC case definition ("Fukuda criteria")* (CDC-1994)
 * 2005 CDC case definition ("Reeves criteria")*

The Holmes criteria is currently not in use. The Oxford criteria is used in the UK by clinicians and researchers. Fukuda criteria is used in research by several countries including the US and sometimes in the UK. Reeves criteria is currently being used in the NIH Post-Infectious ME/CFS Study but overall it is not in use.

Combined (ME/CFS)

 * 2003 Canadian Consensus Criteria (CCC)
 * 2007 NICE guidelines*

The Canadian Consensus Criteria is sometimes used by clinicians and for research in many countries but has not been officially adopted by most countries including the USA. NICE guidelines are used by clinicians in the UK.

Note: ME/CFS (or CFS/ME in the UK and parts of Europe) is the acronym now used in the US and some other countries.

SEID

 * 2015 IOM diagnostic criteria (SEID)

Proposed for use in the USA in clinical settings but has not been officially implemented. The NIH Post-Infectious ME/CFS Study is using this criteria along with three other criteria.

The Centers for Disease Control and Prevention (CDC) outlines the IOM diagnostic criteria under the ME/CFS page "IOM 2015 Diagnostic Criteria".

Note on Definition flaws
Definitions with a asterisk (*) are considered to be by most ME/CFS patients, many ME/CFS patients groups, and several ME/CFS researchers as being seriously flawed in that these criteria capture individuals suffering from Chronic Fatigue and not Chronic Fatigue Syndrome, Myalgic Encephalomyelitis or Systemic Exertion Intolerance Disease.

Comparison

 * 2003,
 * 2012,
 * 2015, Accurate diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome based upon objective test methods for characteristic symptoms (Frank Twisk)
 * 2015, Case Definition Comparison - Graph 1
 * 2016, Chronic Fatigue Syndrome versus Systemic Exertion Intolerance Disease (Leonard Jason)
 * 2017, Patients diagnosed with Myalgic encephalomyelitis/chronic fatigue syndrome also fit systemic exertion intolerance disease criteria (Lily Chu), (Jane Norris), (Ian Valencia) & (Jose Montoya)

Learn more

 * CFS vs SEID - Tandfonline The Four-symptom criteria is noted.
 * CFS and ME: Toward An Empirical Case Definition - NCBI - NLM - NIH.gov See: Graph - 1
 * Excluding Factors: Jason Critiques the IOM Definition for ME/CFS - Health Rising - Cort Johnson The Four-symptom criteria is noted.