Research Diagnostic Criteria

 

These diagnostic criteria have been designed for research use only.

 Oxford Criteria (UK)
(Sharpe et al 1990)
 
Chronic fatigue syndrome (CFS)
  1. A syndrome characterized by fatigue as the principal symptom.
  2. A syndrome of definite onset that is not life long.
  3. The fatigue is severe, disabling, and affects physical and mental functioning.
  4. The symptom of fatigue should have been present for a minimum of 6 months during which it was present for more than 50% of the time.
  5. Other symptoms may be present, particularly myalgia, mood and sleep disturbance.
  6. Certain patients should be excluded from the definition.

They include:

  1. Patients with established medical conditions known to produce chronic fatigue (eg severe anaemia). Such patients should be excluded whether the medical condition is diagnosed at presentation or only subsequently. All patients should have a history and physical examination performed by a competent physician.
  2. Patients with a current diagnosis of schizophrenia, manic depressive illness, substance abuse, eating disorder or proven organic brain disease. Other psychiatric disorders (including depressive illness, anxiety disorders, and hyperventilation syndrome) are not necessarily reasons for exclusion.

 

Post-infectious fatigue syndrome (PIFS)

This is a subtype of CFS which either follows an infection or is associated with a current infection (although whether such associated infection is of aetiological significance is a topic for research).

To meet research criteria for PIFS patients must:

  • fulfil criteria for CFS as defined above and
  • should also fulfil the following additional criteria:
    1. There is definite evidence of infection at onset or presentation (a patient's self-report is unlikely to be sufficiently reliable).
    2. The syndrome is present for a minimum of 6 months after onset of infection.
    3. The infection has been corroborated by laboratory evidence.

 

 CDC Criteria
(Centers for Disease Control, USA)
(Fukuda et al 1994)
  1. Clinically evaluated, unexplained, persistent or relapsing chronic fatigue that is of new or definite onset (has not been lifelong); is not the result of ongoing exertion; is not substantially relieved by rest; and results in substantial reduction in previous levels of occupational, educational, social, or personal activities; and
  2. the concurrent occurrence of four or more of the following symptoms, all of which must have persisted or recurred during six or more consecutive months of illness and must not have predated the fatigue:
  • self-reported impairment in short-term memory or concentration severe enough to cause a substantial reduction in previous levels of occupational, educational, social or personal activities.
  • sore throat
  • tender cervical or axillary lymph nodes
  • muscle pain
  • headaches of a new type, pattern or severity
  • unrefreshing sleep
  • post-exertional malaise lasting more than twenty four hours
  • multijoint pain without joint swelling or redness

 

 Australian Criteria
(Lloyd et al 1988)
 
  1. Disabling and prolonged feelings of physical tiredness or fatigue, exacerbated by physical activity.
  2. Present for at least 6 months.
  3. Unexplained by an alternative diagnosis reached by history, laboratory, or physical examinations.
  4. Accompanied by the new onset of neuropsychological symptoms including impaired short-term memory and concentration, decreased libido, and depressed mood. These symptoms usually have their onset at the same time as the physical fatigue, but are typically less severe, and less persistent than those seen in classic depressive illness.

Patients are excluded if:

  1. They have a chronic medical condition that may result in fatigue.
  2. There is a history of schizophrenia, other psychotic illnesses, or bipolar affective disorder.

In addition, drug or alcohol dependence makes CFS very unlikely.

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