Standard Medical Tests

As a syndrome that is identified by both the presence of specific symptoms, as well as the absence of positive test results for similar diseases, fibromyalgia is often challenging to diagnosis. Individuals may only have mild symptoms initially and may not even report the symptoms to a doctor until they have become much more severe and debilitating. To add to the time it takes to get a diagnosis is the seemingly endless medical tests that need to be completed to rule out other health conditions that may have similar or overlapping symptoms. All this can lead to a great deal of frustration on the part of the patient as well as for the medical professional, employer, family members and friends.

Although there is not one specific test that conclusively determines the diagnosis of fibromyalgia, there are standard medical tests that can be used to rule out those overlapping conditions. However, it is important to realize that people with fibromyalgia may have one or more diseases or medical conditions that have similar symptoms. In addition, individuals with fibromyalgia can also have more than one type of chronic pain syndrome which can further complicate the use of standard tests to pinpoint the problem.

Thyroid Tests

Thyroid conditions are often associated with the same symptoms as fibromyalgia, including extreme fatigue, sleep problems, widespread pain and a variety of other symptoms including tingling in the extremities. Very commonly, doctors will obtain a TSH or thyroid stimulating hormone test. This is a simple blood test that checks the level of TSH in the blood.

If a patient has hypothyroidism, the thyroid does not produce enough thyroid hormone and the patient experiences fatigue, constant feelings of cold in the body, constipation, skin changes, and pain in the limbs. This is relatively common in the general population and can be a result of several factors including chronic stress and pain, injury, illness or genetic factors.

Red Blood Cell Count

The red blood cells in the body are responsible for carrying oxygen to the cells through a transporter molecule that is known as hemoglobin. The cells of the body require the oxygen that the red blood cells carry to correctly function and complete their metabolic activity. When red blood cell levels are low, a condition known as anemia, the cells of the body and brain do not function properly. Common symptoms of anemia include extreme fatigue and mental exhaustion, dizziness, problems with concentration, leg cramps, insomnia and headache, tingling in the hands or feet, abdominal pain and constipation which are all symptoms that are also seen with fibromyalgia.

Anemia can be caused by many different factors including injury, internal or external bleeding, genetic factors, iron deficiency, vitamin deficiency, destruction of red blood cells in the body, poisoning and kiney disease. It is essential to rule out anemia as the cause of the symptoms through a simple red blood cell test that can be done at any clinic or lab. Any decrease in the normal range of red blood cells should be investigated and treated immediately to restore red blood cell levels and address the root of the problem.


One of the major differences between the joint pain associated with fibromyalgia and the joint pain associated with inflammation and infections is that there is typically no swelling, redness or heat on the painful joints or areas of the body with fibromyalgia. When inflammation is present there will be additional heat, swelling and possibly redness to the injured, damaged or infected area of the body.

The two most common tests to look for generalized inflammation are the Erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) levels. If either the ESR or CRP is elevated, it is less likely that fibromyalgia is the cause of the symmptoms and your doctor will look for other causes. Treating the cause of the inflammation as well as using nonsteriodal anti-inflammatory drugs (NSAIDs), antibiotics or corticosteroids often eliminates the pain and discomfort caused by inflammation shortly after drug therapy is started. For those with fibromyalgia these therapies may offer slight relief but not complete or comprehensive relief of the pain and joint stiffness.

Substance P

One new and very promising test is the presence of Substance P in the cerebral spinal fluid of patients with fibromyalgia. This is different than the normal Substance P levels found in patients that are diagnosed with chronic fatigue syndrome and may be a key in helping to determine which condition is present in patients. 3

Substance P is linked with the modulation and control of stress, anxiety, depression and pain and is found in elevated levels in those with fibromyalgia. The specific genetic markers and genetic factors that lead to elevated Substance P is not understood at this time, but does provide options for further research to identify individuals that may be at risk for the development of fibromyalgia at a much earlier stage. However, this test is currently only used in research studies and is not widely available for testing.


1 Olateju, T. O., & Vanderpump, M. P. (2006). Thyroid hormone resistance. Annals of Clinical Biochemistry , 431-440.

2 Garrison, R. L., & Breeding, P. C. (2003). A metabolic basis for fibromyalgia and its related disorders: the possible role of resistance to thyroid hormone. Medical Hypotheses , 182-189.

3 Ablin, J. N., Bar-Shira, A., Yaron, M., et al. (2009). Candidate-gene approach in fibromyalgia syndrome: association analysis of the genes encoding substance P receptor, dopamine transporter and α1-antitrypsin. Clinical and Experiemental Rheymatology , S33-S38

This article was originally published on July 11, 2012 and last revision and update of it was 9/7/2015