How is chronic fatigue syndrome (or systemic exertion intolerance disease) diagnosed?
Chronic fatigue syndrome (CFS) or SEID is a diagnosis made by excluding many diseases that have chronic fatigue as a major or frequent symptom. Unfortunately, there are no physical signs or diagnostic tests that identify CFS. The diagnosis is made by fitting the two major criteria set out by a group of CFS research experts.
The first criteria states the patient must have severe chronic fatigue of six months or longer duration with other known medical conditions excluded by clinical diagnosis (a diagnosis by exclusion).
The second criteria requires the patients have four or more of the following symptoms that either occurred at the same time or after the severe chronic fatigue. The symptoms are substantial impairment in short-term memory or concentration; sore throat; tender lymph nodes; muscle pain; multi-joint pain without swelling or redness; headaches of a new type, pattern or severity; unrefreshing sleep; and post-exertion malaise lasting more than 24 hours.
Although there are no lab studies that identify CFS, lab studies do provide some supportive evidence for a diagnosis. Lab studies that confirm either the presence or absence of cause of other diseases help define the diagnosis of exclusion. Additionally, many patients with CFS have certain lab findings listed below:
- Very low erythrocyte sedimentation rate (ESR)
- Elevated immunoglobulins against Coxsackie B virus, HHV-6 (human herpes virus strain 6), and/or Chlamydia pneumoniae
- Decreased number of natural killer cells
- Normal CBC, liver function tests, and normal urinalysis
When taken as a group, these tests support a diagnosis of CFS but are not definitive; only the patients who meet the two established criteria for CFS are definitively diagnosed with CFS.
Below is the new proposed criteria for SEID; the new report used an older designation (ME/CFS) but the criteria are for SEID; this fact shows the medical terminology problems when new names of diseases are proposed.