Health A-Z

Medical Content Created by the Faculty of the Harvard Medical School



Although there is a lot of evidence that chronic fatigue syndrome is caused by a physical problem involving the immune system, energy metabolism and the nervous system, there is no laboratory test or procedure to confirm the diagnosis. Until a better way is found, doctors must diagnose chronic fatigue syndrome based on whether a person has the symptoms of the illness and by eliminating other illnesses that can cause long-lasting fatigue.

For this reason, your doctor will ask about symptoms of other fatigue-causing illnesses including:

  • Hypothyroidism (underactive thyroid gland)

  • Adrenal insufficiency (underactive adrenal gland)

  • Heart disorders

  • Sleep apnea or narcolepsy

  • Side effects of medications

  • Cancer

  • Hepatitis B or hepatitis C

  • Certain psychiatric illnesses, especially major depression, bipolar disorder, schizophrenia and delusional disorders and dementia

  • The eating disorders anorexia nervosa and bulimia

  • Drug abuse, including alcohol abuse

  • Severe obesity

Your doctor will examine you and assess your mental status. Some basic blood tests may be ordered, such as a red blood cell count (hematocrit), white blood cell count and differential white blood cell count, thyroid, kidney and liver tests. Additional, more specialized testing may be needed, including testing of your autonomic nervous system.

Page 3 of 9     Next Page:  Chronic Fatigue Syndrome Expected Duration
Click here to to redeem your SparkPoints
  You will earn 5 SparkPoints
From Health A-Z, Harvard Health Publications. Copyright 2007 by the President and Fellows of Harvard College. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.

You can find more great health information on the Harvard Health Publications website.