Fibromyalgia Diagnosis

Expect Lots of Testing

The circles show the 18 tender points sometimes used to diagnose fibromyalgia. Creative RM/Getty Images

Fibromyalgia is a difficult condition to diagnose. So far, we don't have a lab test that's fully accepted by the medical community, and no scans or images can nail down a diagnosis, either. Because of that, fibromyalgia is a diagnosis of exclusion.

That means before doctors can diagnose it, they need to rule out a host of other conditions with similar symptoms. Typically, you can expect them to order blood tests for hypothyroidism (low thyroid hormone), infections, polymyalgia rheumatica, rheumatoid arthritis and lupus.

Doctors may also order other lab and imaging tests, depending on your symptoms.

Fibromyalgia is typically diagnosed and treated by rheumatologists. The American College of Rheumatology (ACR) in 1990 established the first diagnostic criteria for fibromyalgia.

However, in May 2010 the ACR put out new provisional criteria, not to replace the old ones but to address certain limitations. The goal was to provide a more practical approach that allows doctors to get a better understanding of your unique set of symptoms as well as how sick you are overall. Both sets of criteria are considered perfectly valid and acceptable for diagnosing fibromyalgia. Doctors can use whichever one their most comfortable with, or they may even use both of them.

1990 Fibromyalgia Diagnostic Critieria

Under the 1990 criteria, pain was the only symptom mentioned. Once other possible conditions were ruled out, a fibromyalgia diagnosis required:

  • Pain in all four quadrants of the body and in the axial skeleton (bones of the head, throat, chest and spine) that's been present on a more or less continuous basis for at least three months.
  • Pain in at least 11 of 18 tender points, which are specific spots on the body that hurt when pressure is applied. (See the illustration above for the location of tender points.)

    The tender-point exam has long been criticized for being too subjective, and not all doctors are comfortable with their ability to administer the exam. Some studies showed it was only accurate about 75 percent of the time, as well.

    2010 Fibromyalgia Diagnostic Criteria

    The new fibromyalgia diagnostic criteria take into account many more symptoms and have a built-in way for doctors to monitor your symptom severity. They also provide some flexibility; one weakness of the tender point exam is that your pain threshold can fluctuate, meaning you'll have different results at different times. The researchers behind this method say the new criteria are about 88 percent accurate.

    As with the old criteria, other possible conditions must be ruled out, and symptoms must have been present for at least 3 months. They also include 2 new methods of assessment: the widespread pain index (WPI) and the symptom severity (SS) scale score.

    The WPI is a list of 19 areas of the body. All you have to do is indicate which of those areas you've had pain in over the past week.

    Each "yes" is one point, so the score ranges from 0-19.

    For the SS scale score, the patient ranks specific symptoms on a scale of 0-3. These symptoms include:

    The numbers assigned to each are added up, for a total of 0-12.

    For a diagnosis, you need EITHER:

    1. WPI of at least 7 and SS scale score of at least 5, OR
    2. WPI of 3-6 and SS scale score of at least 9

    A PDF document with the full criteria is available online. It includes the 19 areas in the WPI and a longer list of somatic symptoms: Fibromyalgia Diagnostic Criteria.

    Who Diagnoses Fibromyalgia?

    Since the 1990s, fibromyalgia primarily has been treated by rheumatologists, but now that it's being regarded more as a neurological condition, some neurologists also are treating it, as well. Even so, it can be difficult to find a doctor who's willing and able to effectively diagnose and treat fibromyalgia.

    A lot of questions and problems can come up along the road to diagnosis. This article can help you navigate some of the common ones:

    Source:

    American College of Rheumatology, 2007. "Fibromyalgia"

    Wolfe F, et al. Arthritis Care & Research. 2010 May;62(5):600-10. The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.

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