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At this time, there is no test that can be used to diagnose CFS. The syndrome is diagnosed by exclusion through:

  • Documenting the patient’s medical history
  • Performing a thorough medical examination
  • Conducting cognitive function tests
  • Ruling out other conditions that may be causing or exacerbating the fatigue (and/or identifying and treating those that can be treated)
  • Fulfilling the criteria for the CDC definition of CFS
  • Monitoring the patient over time to see if other underlying conditions arise

Laboratory tests can be useful to help diagnose conditions with similar symptoms and disorders that must be identified and treated before a diagnosis of CFS can be made. The CDC recommends a few general tests, listed in the next section.

Laboratory tests

Other tests may be ordered to follow up abnormal findings on the general tests and as warranted by a patient’s symptoms. These additional tests are used to help identify or rule out diseases and disorders that may be causing fatigue; they are not capable of directly diagnosing CFS.

These other tests may include:

  • ANA (antinuclear antibodies) ordered when an autoimmune disorder is suspected
  • TB skin test to check for exposure to the mycobacterium that causes tuberculosis
  • Lyme disease test when suspected and endemic in the patient’s geographical area. There is no proven evidence that Lyme disease can be acquired in Australia. In addition, the tick species present in Australia do not have the requisite life cycles to allow development of the Lyme disease causing bacterium.
  • Rheumatoid factor / CCP to determine whether rheumatoid arthritis may be present
  • HIV antibody test to check for HIV infection
  • Cortisol / ACTH when low cortisol concentrations and/or decreased adrenal gland function are suspected

Routine viral testing, such as for CMV (cytomegalovirus), EBV (Epstein Barr virus), herpes, enterovirus, adenovirus, and testing for candida albicans (yeast) is not diagnostic for CFS and is not recommended.

Other laboratory tests may be used in a research setting to attempt to better understand the cause and course of CFS but are not considered clinically useful at this time.

Non-laboratory tests
Occasionally, an MRI (magnetic resonance imaging) scan may be ordered to help rule out multiple sclerosis (MS) as a cause for a patient’s chronic fatigue. This would only be done when symptoms suggestive of MS are present. Other tests and imaging scans may be used in a research setting but are not considered clinically useful at this time.

Last Review Date: April 1, 2018