Are ME and CFS same?
No.
Chronic Fatigue Syndrome (CFS) is defined by the diagnostic criteria The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group or widely known as Fukuda criteria (1994).
Myalgic Encephalomyelitis (ME) is defined by the diagnostic criteria Myalgic encephalomyelitis: International Consensus Criteria (2011).
International Consensus Criteria (ME (ICC)) distinguishes ME from CFS.
The label ‘chronic fatigue syndrome’ (CFS) has persisted for many years because of the lack of knowledge of the aetiological agents and the disease process. In view of more recent research and clinical experience that strongly point to widespread inflammation and multisystemic neuropathology, it is more appropriate and correct to use the term ‘myalgic encephalomyelitis’ (ME) because it indicates an underlying pathophysiology. It is also consistent with the neurological classification of ME in the World Health Organization’s International Classification of Diseases (ICD G93.3).
What is ME/CFS, then?
ME/CFS is defined by the diagnostic criteria Canadian Consensus Criteria (CCC) 2003.
It is also used as an umbrella term for at least 20 sets of case definitions or diagnostic criteria currently exist. When you see the expression “CFS, also known as ME”, it indicates the article is describing umbrella term ME/CFS, not CCC.
Which diagnostic criteria should I use?
While using umbrella term can be beneficial for collaborative advocacy, identifying the diagnostic criteria is critical for meaningful medical research and appropriate clinical care strategy.
We encourage CFS and ME/CFS patients to upgrade their diagnosis to ME where applicable.
There seems to be a myth that only severe patient would be diagnosed with ME. ME (ICC) recognises four symptom severity: mild, moderate, severe, and very severe. We empathise each severity has own challenges in managing/treatment and carrying on with everyday life.
The clinical guideline, the International Consensus Primer for Medical Practitioners (ICP) can be downloaded on What is ME? page. It can also be downloaded on National Health and Medical Research Council (NHMRC) webpage.
Disclaimer: This article is not intended for medical advice. In the absence of accessible and knowledgeable ME doctors, we recommend asking ME related questions at reputable forums, such as Phoenix Rising and Science for ME.