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Tests For Chronic Fatigue Syndrome

Written by Dr. Diane Mueller:  Proper tests for chronic fatigue syndrome (CFS) is important to understand as it’s a debilitating condition that affects millions of people worldwide. 

While people are commonly told that there is no cause for chronic fatigue syndrome, this is simply not true. The body does not just decide one day to be fatigued, there is a reason behind it. Several tests are often done by conventional medicine to rule out some common reasons for chronic fatigue syndrome. Much of the time, these tests are normal. 

In this blog on “tests for chronic fatigue syndrome” we will first cover some of the most common standard testing done for determining the cause of the fatigue. Continue reading as later in the blog we will explore some of the commonly MISSED tests for chronic fatigue syndrome.

tests for chronic fatigue syndrome

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Common Tests for Chronic Fatigue Syndrome

Blood Tests

Blood tests are often the first tests ordered by doctors when investigating a possible case of CFS. These tests are often the following: 

Tests looking for thyroid problems: TSH, Free T3, Free T4, Reverse T3 and Thyroid antibodies (much of the time, people do not have full thyroid tests run). 

  • Adrenal tests: DHEAs and cortisol
  • Anemia testing, Vitamin D testing and testing for other nutrient deficiencies
  • Testing for EBV and CMV (viruses that cause mono)
  • Testing for autoimmune conditions. 

For many people either these tests are normal or treating for these conditions does not eliminate the fatigue. In this case other common tests that are run are as follows: 

Exercise Stress Test

An exercise stress test, also known as a cardiopulmonary exercise test (CPET), measures how well your heart, lungs, and muscles respond to physical activity. During the test, you will be asked to walk on a treadmill or ride a stationary bike while your heart rate, breathing, and oxygen levels are monitored. This test can help identify abnormalities in your cardiovascular and respiratory systems, which can occur in people with CFS.

Sleep Studies

Many people with CFS also experience sleep disturbances, such as insomnia, sleep apnea, or restless leg syndrome. Sleep studies, also known as polysomnography, can help identify these conditions and determine if they are contributing to the fatigue. During a sleep study, you will be monitored while you sleep to track your brain waves, breathing, heart rate, and other functions. A simple at home sleep study test is called a nocturnal oximetry test. 

Neurological Tests

CFS can also affect cognitive function, such as memory, attention, and concentration. Neurological tests, such as a neuropsychological evaluation or brain imaging, can help identify any abnormalities in brain function that may be contributing to the fatigue.

Postural Orthostatic Tachycardia Syndrome (POTS) Test

POTS is a condition in which your heart rate increases significantly when you stand up, leading to dizziness, lightheadedness, and fainting. This condition is common in people with CFS. A POTS test involves measuring your heart rate and blood pressure while you lie down, sit up, and stand up. This can help identify any abnormalities in your cardiovascular system that may be contributing to the fatigue.


Tests for Chronic Fatigue Syndrome (You Probably Didn't Hear About)

Now let’s talk about test for chronic fatigue syndrome that are commonly missed.

At My Lyme Doc, we work with a lot of clients who have had CFS for years or even decades. While it is common that those with CFS have a level of thyroid and adrenal imbalances, these are only portions of the problem. Many times, thorough testing for thyroid and adrenal function is not completed, but even it if is, it is only a piece of the puzzle. 


Other root causes of chronic fatigue syndrome that are common, but not tested for include: 


  • Chronic Hidden Infections
  • Environmental toxins such as metals, plastics, herbicides, and pesticides
  • Mold and mold toxins
  • Chronic recurring viral infections

Sometimes people have had testing for chronic hidden infections such as Lyme Disease, but the test was not adequate. Oftentimes a sub-par test is used, and a disease process is ruled out, but it is a false negative. For information on testing for chronic hidden infections, please see our blog called Lyme Disease Test to learn about how to get adequate testing done.

The most important thing to remember is that there is a reason why your body is manifesting fatigue. Continue to work to find someone that can get to the root cause and avoid those that tell you that you must live with it or there is nothing that can be done. There are answers. There is hope. If you need any help, please contact us by booking a free health evaluation call where we will help determine if our approach and team can help you. 

This can be booked at:

For more information on Chronic Fatigue Syndrome See our Blog Below

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The Causes or Mechanisms of Action

Despite the sometimes-similar symptoms, the MOAs of these two conditions are very different:

  • Lyme Disease is caused by the bacteria Borrelia burgdorferi and Borrelia mayonii. Lyme is a bacterial infection.
  • The cause of Fibro is much less clear and could involve genetic, hormonal or other factors. Gut health may play a role too. But the primary MOA is thought to be a dysfunction of pain sensitization. You can read more in our FM blog here.  
  • Fibromyalgia is often triggered by a stressful event, including an infection, trauma (due to an accident, serious injury or divorce) or major surgery. FM can actually be triggered by an infection like Lyme Disease.

What is the Link?

Similar Symptoms & Mis-Diagnosis

  • FM can be mis-diagnosed as Lyme disease.
  • Late-stage chronic Lyme disease can be mistaken for FM.
  • Lyme Disease can trigger Fibromyalgia.

So how do we differentiate between LD and FM?

How do we untangle symptoms and identify a case of chronic Lyme disease vs post-infectious Fibromyalgia?

We need to do a thorough exam, the correct labs and a deep analysis of the overlapping symptoms. There are other things to look at to get a correct diagnosis. These include:

  • A history of a bulls-eye rash, a tick bite or spending time in areas where Lyme Disease has been reported are good indicators that it could well be Lyme.
  • Antibiotics should improve Lyme Disease symptoms, while they don’t help in the case of Fibromyalgia.
  • Pain in specific tender points is associated with Fibromyalgia more than other illnesses.
  • Stiffness in Lyme Disease occurs mainly in the neck and joints. In Fibromyalgia, it is usually widespread pain.
  • Lyme Disease can cause arthritis symptoms and swollen joints, especially in the knees. Fibromyalgia causes pain and stiffness but doesn’t typically involve swelling or damage to the joints.

In our clinic, we have expertise in treating a range of complicated, difficult-to-diagnose conditions like Fibromyalgia and Lyme Disease. We look for the root causes in our patients to identify what could be causing the symptoms. We regularly treat and resolve Lyme, chronic infections and other complex conditions in patients in our Functional Medicine clinic.

Have Lyme Disease or suspect that you do?

We have helped thousands of
people restore their health
and quality of life by diagnosing
and treating their Lyme Disease.

“Dr. Mueller’s approach to medicine is refreshing! There is only so much you can do with western medicine and in my life I was needing a new approach.  By addressing the whole body, nutritional diet factors, environmental factors, blood work, and incorporating ideas I had not previously known, I was able to break through with my conditions.  I am not only experiencing less pain in my life, but through the process of healing guided by Dr. Diane Mueller, I am now happy to say I have more consciousness surrounding how I eat, what to eat and when things are appropriate.  Living by example Dr. Mueller has a vibrancy that makes you want to learn and know more about your body and overall health.  I highly recommend her to anyone looking for new answers, a new approach to health, or in need of freedom from pain and limitations.”

-Storie S.

Kihei, HI

Lyme Disease is Often Misdiagnosed as Fibromyalgia, Chronic Fatigue, Depression,
or Other Illnesses

Have Mold Illness or Lyme Disease or suspect you do?

We have helped thousands of people restore their health and quality of life by diagnosing and treating their Mold Illness, Lyme Disease and other root causes.

End Chronic Fatigue, Pain, Brain Fog &
More Taught By Expert Dr. Diane Mueller