Diagnosing ME/CFS

Early diagnosis ensures patients receive management that may reduce the risk of their condition deteriorating.  It also enables referral for vital support services and provides answers for the patient and their loved ones.  

Patients with Long COVID who present with post-exertional malaise (PEM) should have ME/CFS included in the differential diagnosis as the presence of PEM may change activity and exercise advice.  

ME/CFS Professional Development

Healthcare practitioners can access two Royal Australian College of General Practitioners (RACGP) CPD online education modules, which include information on how to accurately diagnose ME/CFS. These modules are produced by ThinkGP and sponsored by Emerge Australia. 

A thorough medical workup is required for a diagnosis of ME/CFS, which includes medical history, physical examination, appropriate tests and differential diagnosis. 

National Academy of Medicine clinical criteria: 

The National Academy of Medicine (NAM) criteria [1] are recommended for clinical settings by the Centers’ for Disease Control (CDC) and Emerge Australia, as they were designed for diagnosis in the clinical setting. 

Image from Institute of Medicine 

Other common symptoms include, but are not limited to: 

  • muscle pain 
  • joint pain without swelling or redness 
  • headaches of new type, pattern or severity 
  • swollen or tender lymph nodes 
  • frequent or recurring sore throat  
  • feeling cold or hot, may include night sweats 
  • light, sound or olfactory sensitivity 
  • chemical sensitivity including sensitivity to medication 
  • gastrointestinal and genitourinary symptoms 
  • muscle weakness, that may fluctuate. 

If a patient is presenting with signs and symptoms that raise the possibility of ME/CFS or Long COVID, it is important they rest and pace their activity while a diagnostic workup occurs. Advising patients to engage in activity that provokes symptoms is no longer recommended. – NICE Guidelines (2021) [2].

Diagnosing ME/CFS may take several visits. Discuss with your patient how best to balance multiple medical visits with their energy limitations.  

Keep in mind some patients may not appear unwell during clinic visits, but recovery time may be required. More severe patients may not be able to leave the house, even for medical appointments. 

Paediatric and adolescent ME/CFS diagnosis

The current diagnostic criteria for paediatric and adolescent ME/CFS are available here:
“Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Diagnosis and Management in Young People: A Primer”

Laboratory Tests 

While there are no diagnostic tests sensitive and specific enough to diagnose ME/CFS, tests can look for other conditions, or guide clinical management. A list of routinely performed tests can be found here.

Functional Impairment

Significant reduction in capacity compared to pre-illness function is always present in ME/CFS. This may fluctuate and it will be individual.   

Establishing your patients’ patterns of activity can be a useful insight into the impact of their symptoms. You and your patient may find it helpful for them to fill out an activity diary for a week or two, to review at their next appointment. Click here for Emerge Australia’s Activity Symptom Tracker template.

Documenting functional impairment in the medical record has several benefits: 

  • Establishes a baseline to assess the impact of treatment and management 
  • Provides crucial evidence for claiming Centrelink benefit, NDIS support, income protection or other insurance. 

The World Health Organization have created a detailed Disability Assessment Schedule (WHODAS) which can be accessed here.

Cardinal Symptom: post-exertional malaise  

The cardinal symptom of ME/CFS is post-exertional malaise (PEM). PEM is the exacerbation of symptoms following physical or mental exertion. 

The level of exertion which will trigger PEM varies according to illness severity and may change over time. Often ordinary, daily activities such as showering, attending a medical appointment, or reading trigger PEM. 

Patients may already be pacing activity to avoid PEM. Ask your patient if they are already pacing to manage energy.  

Further distinguishing features of PEM include:

  • Delayed onset: symptom exacerbation may occur 24 to 48 hours after exertion 
  • Variable and often prolonged period of recovery to baseline illness severity and symptoms. 

Patients may use language such as “crash”, “relapse” or “collapse” to describe PEM.  

The DePaul PEM questionnaire may be helpful to establish if a patient is experiencing PEM. 

Unrefreshing Sleep 

Sleep may be unrefreshing or there may be circadian rhythm disturbances with day/night reversal. Problems with sleep onset, staying asleep or waking early are also common.  

There may be a primary sleep disorder present such as narcolepsy or sleep apnoea and sleep studies may be required.  

Patients can use the sleep and pain profile to assess their sleep. 

Cognitive Impairments 

Most people with ME/CFS have problems with one or more of these areas [3]: 

  • working memory  
  • attention  
  • processing speed  
  • attention deficits. 

Cognitive impairment may be induced or exacerbated by exertion, both physical or mental. This means that cognitive capacity may fluctuate and has real-world consequences for maintaining employment, study or activities of daily living.

Patients often describe this symptom as “brain fog” or “can’t think straight”.

Orthostatic Intolerance 

Orthostatic intolerance occurs when symptoms become worse with upright positions (raised head of bed, sitting or standing) and generally improve when recumbent.

The most common forms of orthostatic intolerance (OI) in ME/CFS are:

  • Neurally-mediated hypotension (NMH)
  • Postural orthostatic tachycardia syndrome (POTS).

However, research suggests symptoms of OI also occur without BP or HR changes [4]. This symptom may be established by careful questioning including:

  • How do they feel when sitting or standing?  
  • How long can they sit or stand??  
  • How does hot weather effect them?  
  • Do they study or work lying down, in bed or a recliner? Do they prefer to sit with knees to chest or legs under them? 

Fainting is not seen in all patients with OI.  

Some patients may exhibit dependent acrocyanosis, especially in hot environments like the shower.  

OI can be assessed in the office using the NASA lean test, or a referral for a tilt table test can be made. 

Orthostatic challenge can bring on PEM and testing may not be suitable for more severe patients.  

Exclusionary Conditions

Identify and manage other conditions that may explain symptoms. Once these are treated and stabilised, further consideration of an ME/CFS diagnosis can be made. The American CDC has a list of many of these conditions listed here.

Co-occurring Conditions  

Co-occurring conditions are common in ME/CFS and do not necessarily rule out an ME/CFS diagnosis. Identifying and managing these may reduce symptom burden [5]. Common co-occurring conditions are listed here.

Diagnostic Resources 

NAM Clinicians’ Guide 

CDC ME/CFS Assessment Overview 

CDC ME/CFS Toolkit for Healthcare Providers 

“Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Diagnosis and Management in Young People: A Primer”

Symptom Severity Hierarchy  

Sleep and Pain Profile

Activity Symptom Tracker template

NASA Lean Test 


DePaul PEM questionnaire

IACFSME primer – includes surgical and obstetric considerations.


1. Institute of Medicine (IOM). Beyond myalgic encephalomyelitis/chronic fatigue syndrome: redefining an illness. (2015).
2. NICE. Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management. (2021).
3. Centers’ for disease control. What are ME/CFS Symptoms. https://www.cdc.gov/me-cfs/pdfs/toolkit/What-are-MECFS-Symptoms_508.pdf.
4. van Campen, C. M., Verheugt, F. W., Rowe, P. C. & Visser, F. C. Cerebral blood flow is reduced in ME/CFS during head-up tilt testing even in the absence of hypotension or tachycardia: A quantitative, controlled study using Doppler echography. Clinical Neurophysiology Practice 5, 50–58 (2020).
5. Bateman, L. et al. Diagnosing and Treating Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). U.S. ME/CFS Clinical Coalition https://drive.google.com/file/d/1SG7hlJTCSDrDHqvioPMq-cX-rgRKXjfk/view (2019).

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