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Diagnosis of Chronic Fatigue Syndrome (CFS)

A diagnosis of chronic fatigue syndrome (CFS) is based on the following criteria:
  • Severe, chronic fatigue that lasts for at least 6 months, at least 50% of time, and is not due to another illness or medical cause
  • At least 4 of the following 8 symptoms:
    • Impairment of short-term memory or concentration
    • Sore throat
    • Tender lymph nodes
    • Muscle pain
    • Joint pain without swelling or redness
    • Headaches
    • Sleep that is not refreshing
    • Prolonged fatigue lasting 24 hours or more after exercise
If you have these symptoms, your doctor will conduct more tests. The tests will look for other causes of the symptoms. This may involve:
Your doctor will ask you for a detailed medical history. A complete physical exam will be done.
You will receive a standard series of tests. This should help your doctor identify other possible causes of illness. If no cause is identified, your doctor may make a diagnosis of CFS.
The number and type of tests may vary depending on your history. The following tests are often used to exclude other causes of fatiguing illness:
Specific blood tests can be used to evaluate:
  • Liver function
  • Kidney function
  • Calcium levels
  • Red and white blood cell, and platelet counts—complete blood count (CBC)
  • Electrolyte levels, such as salt and potassium
  • Inflammation—erythrocyte sedimentation rate (ESR)
  • Glucose levels
  • Phosphorus levels
  • Thyroid function—thyroid stimulating hormone (TSH)
  • Total protein levels
  • Iron levels
A urinalysis may be done to check for abnormalities in the urine.
If one of the tests above suggests an illness, your doctor may order more tests. This is done to confirm an illness other than CFS. Additional testing may be done to look for:
Your doctor may want to assess the impact of CFS on certain mental skills. You may have tests for your concentration, memory, and organization. You may also be given a personality assessment. This can help to determine your coping abilities. It is also done to identify any coexisting affective disorders. These may include depression, panic disorder, or other anxiety disorders.

References

Chronic fatigue syndrome. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115094/Chronic-fatigue-syndrome. Updated February 10, 2017. Accessed May 31, 2017.
Chronic fatigue syndrome. Family Doctor—American Academy of Family Physicians website. Available at: http://familydoctor.org/familydoctor/en/diseases-conditions/chronic-fatigue-syndrome.html. Accessed May 31, 2017.
Chronic fatigue syndrome (CFS). Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/cfs/index.html. Updated April 7, 2015. Accessed May 31, 2017.
Craig T, Kakumanu S. Chronic fatigue syndrome: evaluation and treatment. Am Fam Physician. 2002;65(6):1083-1090.
Devanur LD, Kerr JR. Chronic fatigue syndrome. J Clin Virol. 2006;37(3):139-150.
Prins JB, van der Meer JW, Bleijenberg G. Chronic fatigue syndrome. Lancet. 2006;367(9507):346-355.

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