If you talk with a room full of fibromyalgia patients, you're likely to hear quite a few stories describing years of uncertainty prior to finally receiving a fibromyalgia diagnosis.  You'll probably also hear many accounts of being misdiagnosed with other illnesses before doctors determined that they actually had fibromyalgia. 

It's not at all unusual for fibromyalgia to be misdiagnosed as another condition and vice versa.  There are several reasons FM can be difficult to diagnose :

• Many of the symptoms of fibromyalgia are the same as, or very similar to, other illnesses.

• There are no lab tests or imaging scans that definitively identify FM.

• Often people with FM also have other comorbid or overlapping conditions.

Following are 7 other conditions your doctor may consider in trying to determine if you have fibromyalgia, another condition, or both.

1)  ME/CFS (Chronic Fatigue Syndrome)

ME/CFS is the condition that is probably most often confused with FM.  That's understandable since an estimated 70% of people who have one also have the other.  The symptoms of each are remarkably similar.  So much so that some experts believe FM and ME/CFS are slightly different expressions of the same basic illness. 

As with FM, there are no diagnostic tests yet available to definitively identify ME/CFS so diagnosis often comes down to a judgement call by your doctor.

You can learn more about the symptoms, diagnosis and treatment of ME/CFS here:  Chronic Fatigue Syndrome

2)  Hypothyroidism

Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone.  This is another condition that shares a lot of FM's symptomatology.  Some symptoms common to both include joint or muscle pain, fatigue, sensitivity to cold, constipation, depression and weight gain. 

Many doctors rely solely on the TSH test, which measures the amount of thyroid stimulating hormone in your blood, to diagnose hyperthyroidism.  However, in order to get an accurate picture of how your thyroid is functioning, it is also important to test your Free T3 (triiodothyronine) and Free T4 (thyroxine) levels as well. 

For more on hyperthyroidism basics, see: Hyperthyroidism

3)  Lupus

Lupus is an autoimmune disease, meaning the immune system of a person with lupus will attack normal cells as if they were an outside invader.  This can cause inflammation, tissue damage and pain throughout body, which feels very much like the widespread body pain of FM.  There are some symptom differences.  One of the best-known lupus symptoms is the characteristic butterfly-shaped rash that occurs on the cheeks and bridge of the nose of approximately 30% of people with lupus.

Although there is no single test that will identify lupus 100% of the time, there are lab tests that can help your doctor determine whether or not you may have lupus.

For more information on lupus, see:  Lupus (Systemic Lupus Erythematosus)