Chronic Fatigue Syndrome (CFS) Workup

Updated: Aug 29, 2018
  • Author: Jefferson R Roberts, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Laboratory Studies

Laboratory findings are normal in CFS. Tests are used to assess for other underlying causes of fatigue, as follows:

  • Complete blood cell count
  • Chemistries including electrolytes, renal, and liver function tests
  • Thyroid function tests
  • C-reactive protein
  • Erythrocyte sedimentation rate
  • Creatine kinase
  • Cultures, viral titers, cerebrospinal fluid studies (upon high suspicion for infection)

Other Tests

Other tests may include the following:

  • Polysomnography
  • Electrocardiography (ECG)
  • Cardiopulmonary exercise test separated by 24 hours
  • Tilt-table testing

Imaging Studies

Brain Imaging

Computed tomography (CT) or magnetic resonance imaging (MRI) of the brain is useful for ruling out central nervous system (CNS) disorders in patients with otherwise unexplained CNS symptoms. Results of CT scanning and MRI may be normal in patients with CFS. Findings of CNS imaging studies are not specific for CFS and are thus used to rule out alternative explanations rather than to diagnose CFS.