How Do I Know If I Have Chronic Fatigue Syndrome?

Medically Reviewed by Melinda Ratini, MS, DO on February 22, 2023
2 min read

There’s no simple blood test or X-ray to diagnose chronic fatigue syndrome – also known as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). And many of the symptoms of the illness -- deep tiredness, unrelieved by rest or sleep, feeling worse after physical or mental exertion, trouble concentrating, feeling worse after standing and remaining on one’s feet and other symptoms-- are also seen in other conditions, too, making the diagnosis of ME/CFS more difficult.

If you think you might have ME/CFS, make an appointment to see your doctor. Research shows that getting treatment sooner might bring better results.

Your doctor will ask for a lot of information about your health. Unfortunately, there is not yet a diagnostic test that is sufficiently accurate to be useful. Your doctor will need to rule out other conditions or causes before they can diagnose ME/CFS.

They might order other tests like blood and urine tests and scans. They will need the names of all the prescription and over-the-counter medicine you take, in case one of them is causing your symptoms. Also, tell your doctor if you take any supplements. Even so-called “natural” or “herbal” remedies can have side effects, and they might cause problems if used with other medications you’re taking.

Your doctor will give you a complete physical exam and ask you questions about your emotions. This will give them a better idea of what your needs are. It’s important to make sure you don’t have another disorder, which could be serious and could get better with treatment.

Many people who have ME/CFS have other conditions, too. If you get treated for those, it might also improve your chronic fatigue.

 ME/CFS can look a lot like “mono” (mononucleosis), Lyme diseaselupusmultiple sclerosisfibromyalgiasleep disorders, or depression. It affects about 2.5 million Americans, but experts believe only about 20% are diagnosed. 

Your doctor will review your medical history and test results. They will check to see if you have several key symptoms, beginning with extreme tiredness, or fatigue, that doesn’t improve with bed rest for 6 months or longer.

Then, your doctor will check to see if you have three of these "core" symptoms of CFS:

  • Reduced ability to do usual activities for six months or more because of fatigue
  • Worsening of symptoms (difficulty thinking, problems sleeping, sore throat, headaches, feeling dizzy, or severe tiredness). after physical or mental exertion
  • Trouble falling asleep or staying asleep, and awakening unrested

Along with the three symptoms, you must have one of these for a diagnosis of ME/CFS:

  • Problems with thinking and memory
  • Worsening of symptoms while standing or sitting upright; you might feel lightheaded, dizzy or weak, and you may have blurred vision or see spots.

It could take a while to get your diagnosis. It’s OK to ask how you can relieve your symptoms while you wait. Your doctor or health professional will schedule follow-up appointments to see how your treatment is working.