How is chronic fatigue syndrome diagnosed?

Chronic Fatigue Syndrome (CFS) does not have one single test that will allow for the diagnosis thereof to be confirmed. Due to the symptoms of chronic fatigue syndrome mimicking those of a number of other health conditions, patience is often required whilst awaiting a diagnosis.

It is likely that a doctor will first rule out any other diseases and conditions before he or she can diagnose CFS. These conditions may include:

• Sleep Disorders – Sleep disorders can cause chronic fatigue as a symptom. A doctor may conduct an overnight sleep study known as a polysomnogram (PSG). This will record brain activity, blood pressure, heart rate, eye movements, body movements and oxygen levels. Some disorders that may disturb your sleep are insomnia, sleep apnoea and restless leg syndrome.

• Mental health problems – Anxiety, depression, schizophrenia and bipolar disorder are some conditions that have chronic fatigue as a symptom. A psychologist or psychiatrist is able to determine whether one has any of these underlying conditions as the cause of chronic fatigue. The issue with the diagnosis comes in due to chronic fatigue syndrome being able to cause conditions such as depression, therefore adding a complication to the diagnostic process.

• Medical issues – There are a number of medical problems that may result in chronic fatigue as a symptom. These include diabetes, anaemia and hypothyroidism (this is an underactive thyroid). There are lab and blood tests available that can detect any abnormalities in the blood that may be causing certain medical conditions.

A doctor may perform the following tests in order to diagnose chronic fatigue syndrome:

• There are several conditions that can cause chronic fatigue, therefore tests need to be conducted to exclude these conditions. These tests include:
  • Adrenal tests
  • Liver function tests
  • Thyroid tests

If one is suffering from chronic fatigue syndrome, these results will be normal.

• Blood tests will also need to be conducted to help diagnose CFS. Lab tests done on those with CFS have consistently shown that there is an erythrocyte sedimentation rate (ESR) that indicates there is no presence of inflammation, meaning that the ESR is at the extremely low end of a normal reading. An erythrocyte sedimentation rate measures the rate at which the red blood cells settle or sediment over a specific period of time, typically one hour. If the ESR results are elevated or in the range of high to normal, then a diagnosis of CFS is unlikely. A doctor will also be able to detect other conditions from the blood tests, if these are found then CFS will be ruled out.
• A doctor may also order tests known as antibody tests that will aid in determining whether there have been any previous infections such as pneumonia, Epstein-Barr virus (EBV) or Lyme disease that may have caused chronic fatigue syndrome.

• Imaging tests such as an MRI (magnetic resonance imaging) - this is a type of scan that makes use of magnetic fields as well as radio waves that will create detailed visuals of the inside of the body, the MRI scanner consists of a large tube that contains very powerful magnets, a person will lie down inside of this tube for the scan. A CT (computed tomography) scan may also be conducted, this is a type of X-ray. These screening tests allow doctors to rule out any other conditions or disorders of the CNS (central nervous system). If one is sufereing from CFS the results of the tests will be normal.
• Another form of a screening test is known as a positron emission tomography and/or a single-photon emission computed tomography. This test allows for any areas of the brain in the temporal/frontoparietal region with decreased blood flow to be detected. If there is a decreased amount of blood flow in this area, this will explain any cognitive issues experienced due to chronic fatigue syndrome.

Diagnostic criteria for Chronic Fatigue Syndrome

As previously mentioned, in order for the diagnostic criteria for CFS to be met, a sufferer will have experienced inexplicable, persistent fatigue for at least six months or longer. Along with this, the minimum of four of the below symptoms (these have been previously mentioned in symptoms section) will need to be met:

• A sore throat
• Cognitive issues (battling with concentration and memory)
• Muscle pain that is unexplained
• Inflamed lymph nodes in the armpits or neck
• Joint and muscle pain moving from one area to another with no visible redness or swelling
• Unrefreshing sleep
• Extreme exhaustion that lasts for longer than a period of 24 hours after mental or physical exercise
• Headaches with different patterns and severity to those you’ve previously encountered

Chronic fatigue often accompanies several different medical disorders and is therefore not always an isolated symptom. In cases such as these, doctors have stated that a more appropriate term for the condition may be that of chronic multifactorial fatigue.