Information for the public

How CFS/ME is diagnosed

Investigating the symptoms

There is no test to diagnose CFS/ME – doctors diagnose CFS/ME based on your symptoms.

The symptoms of CFS/ME are similar to the symptoms of some other illnesses, and to find out what is wrong (make a diagnosis), your doctor will need to do some tests. There is no specific test that can identify CFS/ME, so the diagnosis has to be based on ruling out other conditions that could be causing your symptoms.

Your doctor should consider CFS/ME if you have disabling tiredness (fatigue) that is new or started suddenly, lasts a long time or keeps coming back and cannot be explained by other causes. CFS/ME should be considered if the fatigue means you can't do the things you used to, if it gets worse after activity or gentle exercise such as a short walk, and if you also have some of the following symptoms:

  • sleep problems

  • pain in the muscles or joints

  • headaches

  • sore throat or sore glands that aren't swollen

  • problems thinking, remembering, concentrating or planning

  • flu-like symptoms

  • feeling dizzy or sick or having palpitations (irregular or fast heartbeats), or

  • exercising or concentrating on something makes your symptoms worse.

Your doctor should consult a specialist if they are unsure about the diagnosis, or if you have severe symptoms.

Because CFS/ME has symptoms similar to many common illnesses that get better on their own, doctors should consider whether a person has CFS/ME if they do not get better as quickly as expected. On the other hand, some other serious illnesses may also have the same symptoms as CFS/ME. So your doctor should take special care to rule these out, particularly if you have any of the following:

  • symptoms such as double vision or blackouts that suggest a problem with your nervous system

  • painful, swollen joints

  • chest or heart problems

  • weight loss

  • signs of stopping breathing for short periods while asleep (called sleep apnoea)

  • persistently swollen glands.

Before making a diagnosis of CFS/ME your doctor should ask you questions about your medical history, do a thorough physical examination, and assess your mental health. They should carry out tests to rule out other causes of your symptoms. These will depend on your symptoms but will include urine and blood tests. Your doctor should consult a specialist if they are unsure about the diagnosis, or if you have severe symptoms.

While you are waiting for a diagnosis or a referral, you should be given advice and help to deal with (or manage) your symptoms so that your everyday life and activities are affected as little as possible.

If a child or young person under 18 years old has symptoms of possible CFS/ME they should be referred to a paediatrician (a specialist children's doctor) within 6 weeks of first seeing their doctor about the symptoms.

If you have new and/or distressing symptoms at any time, you should talk to your doctor about them.

Questions about diagnosis

  • What are the tests you are offering and why am I having them?

  • What do these tests involve? Please give me details.

  • Where will these tests be carried out? Can I have them at home?

  • How long will I have to wait until I have the tests?

  • How long will it take to get the results, and how will I be told about them?

Reaching a diagnosis of CFS/ME

Your doctor should diagnose CFS/ME if your symptoms can not be explained by another cause and have lasted for:

  • 4 months in an adult

  • 3 months in a child or young person (the diagnosis should be made in consultation with a paediatrician).

Your doctor should reassure you that most people's condition improves with time, and many people recover and are able to go back to work and do their normal activities. But you also need to know that some people's symptoms do not improve. For children, the outlook is generally better than for adults.