What investigations should be considered to rule out other conditions in a patient suspected of having ME/CFS?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

When myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is suspected, investigations should be carried out to exclude other diagnoses . These investigations include, but are not limited to:

  • Urinalysis for protein, blood, and glucose
  • Full blood count
  • Urea and electrolytes
  • Liver function tests
  • Thyroid function tests
  • Erythrocyte sedimentation rate or plasma viscosity
  • C-reactive protein
  • Calcium and phosphate levels
  • HbA1c
  • Serum ferritin
  • Coeliac screening
  • Creatine kinase

Clinical judgment should be used to decide on additional investigations to exclude other diagnoses . Examples of such additional investigations include vitamin D, vitamin B12, and folate levels; serological tests if there is a history of infection; and 9am cortisol for adrenal insufficiency . It is important to continue with any assessments needed to exclude or identify other conditions when ME/CFS is suspected .

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