Symptoms
Experts have developed certain criteria to serve as a diagnostic tool for CFS. To differentiate the unknown fatigue as either CFS or idiopathic chronic fatigue (idiopathic means that the cause is unknown), a group of experts has compiled the following criteria (of which, four must have lasted more than six months):

• Short-term memory loss or a severe inability to concentrate, which affects work, school, or other activities.
  
• Sore throat
  
• Swollen lymph nodes in the neck or armpits
  
• Muscle pain
  
• Pain without redness or swelling in a number of joints
  
• Intense or changing patterns of headaches
  
• Inadequate sleep
  
• Weariness, after exertion, that lasts more than one day
  

Last updated: 01-Jan-00