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Table 1 Brief comparison of methods of applying the 1994 case definition of CFS (see text for details)

From: Methods of applying the 1994 case definition of chronic fatigue syndrome – impact on classification and observed illness characteristics

  Method 1 – 1997 Wichita method Method 2 – 2004 Georgia method
Fatigue Telephone interview –
“Severe fatigue, extreme tiredness, or exhaustion”
- Duration 6 months or longer “Yes”
- Rest makes fatigue a lot better
“No” OR “Yes” – Some of the time, a little of the time, or hardly ever
Duration 6 months or longer
MFI-20 General Fatigue ≥13
MFI-20 Reduced Activity ≥10
Functional Impairment Telephone interview – “Yes” to one:
“Has this severe fatigue, extreme tiredness or exhaustion substantially limited …
…your ability to do your usual job or occupation?
…your ability to do your usual educational activities
…substantially limited your social, leisure or recreational activities?”
SF-36 v2
Physical Function ≤70
Role Physical ≤50
Social Function ≤75
Role Emotional ≤66.7
4 of 8 Case Defining Symptomsa During the past month how often have you had < SYMPTOM > − “All the time” OR “Most of the time”
Was < SYMPTOM > bothering you 6 months or longer – “Yes”
CDC Symptom Inventory
<SYMPTOM > frequency X intensity scores summed for 8 case defining symptoms ≥25 and scores for at least 4 symptoms
  1. Abbreviations: MFI-20 multidimensional fatigue inventory-20 questions, SF-36 medical outcomes survey short form-36 questions
  2. aCFS case defining symptoms: post-exertional malaise, impaired memory or concentration, sore throat, tender cervical or axillary lymph nodes, muscle pain, multi-joint pain, new headaches, unrefreshing sleep