FMS Diagnosis

How a Doctor Might Determine if the Chronic Pain One Experiences is Fibromyalgia

The difficulty with diagnosing fibromyalgia is that, in most cases, laboratory testing appears normal and that many of the symptoms mimic those of other rheumatic conditions such as arthritis or osteoporosis.

Most doctors diagnose patients with a process called differential diagnosis, which means that doctors consider all of the possible things that might be wrong with the patient based on, among other factors, the patient’s:

  • Symptoms
  • Gender
  • Age
  • Geographic location
  • Medical history

Physicians then narrow down the diagnosis to the most likely one. The most widely accepted criteria was established in 1990 by the Multicenter Criteria Committee of the the American College of Rheumatology. These criteria, known as “the ACR 1990,” define fibromyalgia according to the presence of the following:

1. A history of widespread pain lasting more than three months
Affecting all four quadrants of the body, i.e., both sides, and above and below the waist.

2. Tender points
There are eighteen designated possible tender or trigger points (although a person with the disorder may feel pain in other areas as well).

During diagnosis, four kilograms of force is exerted at each of the eighteen points; the patient must feel pain at eleven or more of these points for fibromyalgia to be considered. (Four kilograms of force is about the amount of pressure required to blanch the thumbnail when applying pressure.)

While these criteria were originally established for research purposes and were not intended for clinical diagnosis, they have become the de facto diagnostic criteria in the clinical setting.

It should be noted that the number of tender points active at any one time may vary with time and circumstance.

More on Fibromyalgia Syndrome