How to diagnose Chronic Fatigue Syndrome (CFS) ?
Diagnostic Challenges
  
For doctors, diagnosing chronic fatigue syndrome (CFS) can be complicated by a number of factors:
  
   - There's no lab test or biomarker for CFS.
   - Fatigue and other symptoms of CFS are common to many illnesses.
   - For some CFS patients, it may not be obvious to doctors that they are ill.
   - The illness has a pattern of remission and relapse.
   - Symptoms vary from person to person in type, number, and severity.
  
  
These factors have contributed to a low diagnosis rate. Of the one to four million Americans who have CFS, less than 20% have been diagnosed.
  Exams and Screening Tests for CFS
  
Because there is no blood test, brain scan, or other lab test to diagnose CFS, the doctor should first rule out other possible causes.
  
If a patient has had 6 or more consecutive months of severe fatigue that is reported to be unrelieved by sufficient bed rest and that is accompanied by nonspecific symptoms, including flu-like symptoms, generalized pain, and memory problems, the doctor should consider the possibility that the patient may have CFS. Further exams and tests are needed before a diagnosis can be made:
  
   - A detailed medical history will be needed and should include a review of medications that could be causing the fatigue and symptoms
   - A thorough physical and mental status examination will also be needed
   - A battery of laboratory screening tests will be needed to help identify or rule out other possible causes of the symptoms that could be treated
   - The doctor may also order additional tests to follow up on results of the initial screening tests
  
  
A CFS diagnosis requires that the patient has been fatigued for 6 months or more and has 4 of the 8 symptoms for CFS for 6 months or more. If, however, the patient has been fatigued for 6 months or more but does not have four of the eight symptoms, the diagnosis may be idiopathic fatigue.
  
The complete process for diagnosing CFS can be found here.
  
Additional information for healthcare professionals on use of tests can be found here.