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Diagnosis - Chronic fatigue syndrome (CFS/ME)

There's no test for chronic fatigue syndrome (CFS), but there are clear guidelines to help doctors diagnose the condition.

Your GP should ask you about your medical history and give you a physical examination.

They may also offer you tests like blood tests or urine tests to rule out other conditions, such as anaemia (lack of red blood cells), an underactive thyroid gland, or liver and kidney problems.

It can take a while for CFS/ME to be diagnosed because other conditions with similar symptoms need to be ruled out first. 

In the meantime, you may be given some advice about managing your symptoms.

Read more about lifestyle advice for CFS/ME

Guidelines for diagnosing CFS/ME

Guidelines from the National Institute for Health and Care Excellence (NICE) say doctors should consider diagnosing CFS/ME if a patient has extreme tiredness that can't be explained by other causes and the tiredness:

  • started recently, has lasted a long time, or keeps coming back
  • means you can't do the things you used to do
  • gets worse after activity or gentle exercise, such as a short walk

You must also have some of these symptoms:

Your GP should consult a specialist if they're unsure about the diagnosis or if you have severe symptoms.

If a child or young person under 18 has symptoms of possible CFS/ME, they should be referred to a paediatrician within six weeks of first seeing their doctor about their symptoms.

As the symptoms of CFS/ME are similar to those of many common illnesses that usually get better on their own, a diagnosis of CFS/ME may be considered if you don't get better as quickly as expected.

The diagnosis should be confirmed by a doctor after other conditions have been ruled out, and if your symptoms have lasted at least:

  • four months in an adult
  • three months in a child or young person

For more detailed information, see the NICE guidelines on how CFS/ME is diagnosed.

Page last reviewed: 16 May 2017
Next review due: 16 May 2020