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CFS Toolkit - Making a Diagnosis

How to make a diagnosis

In order to diagnose CFS, health practitioners must rule out medical and psychiatric conditions with similar symptoms by giving:

  1. A detailed patient history
  2. A thorough physical examination
  3. Mental status screening
  4. Laboratory screening tests

International CFS Case Definition (1994)

  1. Severe chronic fatigue of 6 months or longer that is not explained by any medical or psychiatric diagnosis
  2. Have 4 or more of the following 8 symptoms:
    • post-exertional malaise lasting more than 24 hours
    • unrefreshing sleep
    • significant impairment in short term memory or concentration
    • muscle pain
    • multi-joint pain without swelling or redness
    • sore throat
    • tender lymph nodes
    • headaches of a new type, pattern, or severity

Recommended laboratory screening tests

  • CBC with differential
  • Total protein
  • Glucose
  • C reactive protein
  • Phosphorus
  • Electrolyte
  • Alkaline phosphatase
  • Creatinine
  • Blood urea nitrogen (BUN)
  • Albumin
  • ANA and rheumatoid factor
  • Globulin
  • Calcium
  • Alanine aminotransferase (ALT) or aspartate transaminase serum level (AST)
  • Thyroid function tests (TSH and Free T4)
  • Urinalysis

Illnesses that may resemble CFS

It is important for persons with symptoms of CFS to consult a physician. CFS symptoms resemble those of many treatable medical and psychiatric conditions. These include sleep disorders, depression, alcohol/substance abuse, diabetes, hypothyroidism, mononucleosis (mono), lupus, multiple sclerosis (MS), chronic hepatitis and various malignancies. Lab tests, medical history, and exams can help identify specific diseases.

If identified conditions are adequately treated and CFS symptoms continue, the patient could be considered to have CFS. This should not prevent continued medical monitoring of the patient.

CFS and other illnesses

People with CFS also are more likely to have obesity, insulin resistance, metabolic syndrome, irritable bowel disease, non-melancholic depression, fibromyalgia, chemical-sensitivity disorder; these conditions should be evaluated if the patient appears symptomatic. It is important for persons with CFS to continue to see their healthcare provider and report changes in symptoms. Sometimes a person diagnosed with CFS may have other symptoms which could be resolved with treatment.


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