What has become known and "The Oxford Criteria" is a definition of CFS published in Journal of the Royal Society of Medicine Volume 84 February 1991 118-121. Every UK study I've read uses it, and I think I've seen other countries who work closely with UK researchers use it as well. I'm going to attach a copy, and hope that it's okay to do this. But I'm also going to summarize here what I think are the key points. The only required symptom is fatigue that is severe, disabling, and affects physical and mental functioning." And that this goes on for 6 months etc. But no other physical maladies are required. No sore throat, post exertion problems, etc. Now, they do mention that a patient may have a mood disturbance, sleep problems, or myalgia. But not one of these is required for diagnosis. In other words, a person can have zero additional physical symptoms (beyond fatigue) and still be diagnosed with CFS. Now, they do have a subtype of their CFS called Post-infectious fatigue syndrome (PIFS). But aside from requiring a previously identified infection, all it requires is the same kind of fatigue for 6 months, etc. as above. The criteria also mentions comparison groups, which is a term they prefer over control groups. Suggested comparison groups are patients with neuromuscular disorder, conditions causing inactivity, and depression. You will notice that they don't suggest researchers compare ME versus their fatigue-only syndrome. Or compare people who have Fukuda. Not that they are required by law to do this, but it is interesting to see what they focus on. Or rather, what they focus away from. So what difference does any of this make. Well, would you like to be given treatment for COPD if the treatment was based on generic coughing studies. I sure wouldn't. But this is the effect this is having on us. And what's worse is, scientists and journalists ignore that this is not the same as other definitions. So they publish articles that list things like sore throat, PEM, etc. but then cite Oxford studies that do not, while all the time ignoring the differences. And journalists do the same. Then everyone reads it and assumes they have done their due-diligence, when they have not.