New Diagnostic Criteria for Fibromyalgia

Tender-point exams are no longer the only way to diagnose fibromyalgia -- the American College of Rheumatology has provisionally accepted alternate criteria for diagnosing the condition and gauging the severity of symptoms.

The diagnostic criteria doctors have been using were established in 1990.  Once other possible causes of symptoms were eliminated, diagnosis was based purely upon pain.  It had to be on both sides of the body, both above and below the waist, along the axial skeleton (head, throat, chest, spine), and also in at least 11 of 18 specific spots on the body that are called tender points.  Symptoms have to have been present for at least 3 months.

The tender-point exam has always been controversial for several reasons.  First, it was originally intended as a qualifier for clinical studies, not as a diagnostic tool.  Second, it's subjective because it relies on a patient's self-reported pain.  Third, because symptoms fluctuate so much, the number of tender points may vary greatly from one exam to another.

Until we have a diagnostic test that's based on blood markers or imaging, we probably won't have a perfect diagnostic test.  (This is true of many diseases, especially neurological ones.)  Still, researchers believe they've come up with something that works better -- they say when the looked at a group of previously diagnosed fibromyalgia patients, the tender-point exam was about 75% accurate, while their criteria caught it 88% of the time.

New Diagnostic Criteria

The new criteria keep the requirements that other causes be ruled out and that symptoms have to have persisted for at least 3 months.  They also includes 2 new methods of assessment, the widespread pain index (WPI) and the symptom severity (SS) scale score.

The WPI lists 19 areas of the body and you say where you've had pain in the last week.  You get 1 point for each area, so the score is 0-19.

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

  • Fatigue
  • Waking unrefreshed
  • Cognitive symptoms
  • Somatic (physical) symptoms in general (such as headache, weakness, bowel problems, nausea, dizziness, numbness/tingling, hair loss)

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

This next part is really interesting to me.  Instead of looking for a hard score on each, there's some flexibility built in, which recognizes the fact that fibromyalgia impacts us all differently, and that symptoms can fluctuate.

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.

What this does is allow for people with fewer painful areas but more severe symptoms to be diagnosed.

Something else I really like about this is that it finally includes cognitive symptoms!  For many of us, "fibro fog" is as debilitating or even more debilitating than pain, yet the old criteria didn't even mention it.  It also recognizes the difference between "fatigue" and "waking unrefreshed," which I believe is an under-recognized distinction in the medical community.

A quick note about "somatic symptoms": strictly speaking, somatic means physical.  The term has gotten a bad rap in the fibromyalgia community because it's been used to suggest our symptoms are the result of somatization, which means "physical manifestations of a psychological illness."  On its own, however, the word somatic does not imply a psychological basis.

The full article on the new criteria isn't yet available for free online, but a PDF of an appendix including these criteria is.  It has the list of painful areas for the WPI and a long list of somatic symptoms that could be considered.  It's here:

If you're undiagnosed or tentatively diagnosed, you may want to take that to your doctor.  Be sure to let him/her know that it's from the American College of Rheumatology and was published in Arthritis Care & Research.

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