Oxford criteria

The Oxford criteria are a set of criteria for the diagnosis Chronic Fatigue Syndrome published in 1991 by a group of psychiatrists. They identify two broad syndromes and are used primarily for research purposes.

Authors
Michael Sharpe, Len Archard, Jangu Banatvala, Leszek Borysiewicz, Anthony Clare, Anthony David, Richard Edwards, Keith Hawton, Harold Lambert, Russell Lane

Chronic fatigue syndrome

 * fatigue is the principal symptom: it is severe, disabling and affects physical and mental functioning; it should have been present for a minimum of 6 months during which it was present for more than 50% of the time.
 * other symptoms may be present: particularly myalgia, mood swings and sleep disturbances.
 * definite onset of symptoms, not life-long.
 * exceptions: patients with established medical conditions known to produce chronic fatigue; also patients with a current diagnosis of schizophrenia, manic depressive illness, substance abuse, eating disorder or proven organic brain disease.

Post-infectious Fatigue Syndrome (PIFS)
A sub-type of CFS which either follows an infection or is associated with a current infection (although whether such associated infection is of aetiological significance (i.e. whether it is the cause of the symptoms) is a topic for research).

To meet the research criteria for PIFS patients must:
 * i. fulfil the criteria for CFS as defined above (i.e. the Oxford definition)
 * ii. should also fulfil the following additional criteria:
 * (a) There is definite evidence of infection at onset or presentation (a patient’s self-report is unlikely to be sufficiently reliable).
 * (b) the syndrome is present for a minimum of 6 months after onset of infection.
 * (c) the infection has been corroborated by laboratory evidence.

PDF for Oxford Definition CFS and PIFS
PDF: A report - chronic fatigue syndrome: guidelines for research - Journal of the Royal Society of Medicine - Volume 84 February 1991 118-121

Criticisms

 * Post-exertional malaise is not a listed symptom. When this symptom is not mandatory, patients with Chronic Fatigue and not the grossly misnamed disease Chronic Fatigue Syndrome are swept into the study.
 * Depression is not an absolute exception for a possible cause of Chronic Fatigue (not to be confused with Chronic Fatigue Syndrome.) This allows for patients with depression to be misdiagnosed with CFS
 * US NIH Report Calls for UK Definition of ME/CFS to be Scrapped - The Argus Report By: Penny Swift "The United States National Institutes of Health (NIH) has issued a draft report that highlights the dire need for scientific research that will help find a cure for the millions of people suffering from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) worldwide. The report also highlights the fact that the decades-old UK Royal Society of Medicine’s Oxford criteria for ME/CFS are severely “flawed,” and that continuing to use these criteria may “cause harm.” Further, the NIH report says that the Royal Society definition should “be retired” and replaced with a single case definition agreed to by the ME/CFS community."

Learn more

 * 2016, AHRQ Evidence Review Changes Its Conclusions