What tests are indicated for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)?

From the Guidelines

ME/CFS diagnosis requires a comprehensive approach, and the indicated tests include those that can help identify underlying biological abnormalities, such as total immunoglobulin tests, natural killer cell function tests, and reactivated herpesvirus panels 1.

Key Tests

• Tilt table or NASA lean test: to evaluate dysautonomia
• Four-point salivary cortisol test: to assess adrenal function
• Small fibre neuropathy biopsy: to identify nerve damage
• Tests looking for abnormal brain perfusion: to evaluate cerebral blood flow

Rationale

These tests are prioritized because basic tests like D-dimer, C-reactive protein (CRP), antinuclear antibody tests, and complete blood count often return normal results in patients with ME/CFS, despite the presence of significant symptoms 1.

Considerations

It is essential to consider the full range of symptoms, including neurological and reproductive system symptoms, and to ask patients about symptom frequency, severity, and disability, particularly postexertional malaise, a cardinal symptom of ME/CFS 1.

From the Research

Diagnostic Tests for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

• ME/CFS is diagnosed primarily by the exclusion of other fatigue illnesses, as there is no single diagnostic test for the condition 2, 3
• Routine blood tests may be used to rule out other conditions and to identify potential biomarkers for ME/CFS, such as:
  • Elevated inflammatory and immune processes 2
  • Ongoing neuro-inflammation 2
  • Decreases in general metabolism and mitochondrial function for energy production 2
  • Abnormalities in sedimentation rate, leukocytes, lymphocytes, neutrophils, monocytes, ferritin, vitamin B12, calcium, alanine transaminase, low-density lipoproteins, and total proteins 4
• Cardiopulmonary exercise testing (CPET) may be used to assess exertion intolerance and post-exertional malaise in ME/CFS patients, including:
  • 2-day CPET procedure to measure baseline functional capacity and provoke post-exertional malaise, then assess changes in CPET variables 24 hours later 5
  • Invasive cardiopulmonary exercise testing (iCPET) to investigate exertional intolerance and potential relationships with small fiber neuropathy (SFN) 6
• Other tests that may be used to diagnose and manage ME/CFS include:
  • Physical examination and medical testing to rule out other fatiguing illnesses 3
  • Orthostatic intolerance (OI) testing to diagnose co-existing medical conditions 3
  • Skin biopsies to identify small fiber neuropathy (SFN) in ME/CFS patients 6