Diagnosing fibromyalgia is quite difficult. Not only are there no lab tests or imaging techniques such as X-ray or MRI that can identify the disorder, there are also a number of other conditions that produce similar symptoms. HIV, Lyme disease, certain types of cancer, degenerative diseases of the spine, and hypothyroidism, among others, can cause fibromyalgia-like symptoms. Tests can rule out many of these conditions, but doing so takes a lot of time, effort, and expense. According to the National Fibromyalgia Association, it takes an average of five years for a fibromyalgia patient to get a proper diagnosis.

Diagnostic Criteria

Until recently, doctors used diagnostic criteria established in 1990 by the American College of Rheumatology (ACR). According to these standards, you had fibromyalgia if both of the following are true:

  • you experience constant pain in all four quadrants of the body (left and right sides, above and below the waist) for at least three consecutive months
  • if you have tenderness in at least 11 of the 18 tender points associated with fibromyalgia

However, many doctors have criticized these criteria. Because fibromyalgia symptoms tend to vary in intensity over time, a person who meets the criteria at one point might not meet them a few hours or days later. The criteria also do not take into account any symptoms not related to pain, such as fatigue and depression.

A New Way of Diagnosing Fibromyalgia

In May 2010, the ACR published an update to their 1990 report that established the diagnostic criteria for fibromyalgia. While the ACR still recognizes the importance of tender points, the new report decreases their significance in the diagnostic process. Instead, the ACR has proposed a new widespread pain index (WPI) that involves a checklist of 19 areas of the body. If the patient has felt pain in the specific area in the past seven days, a check is made and a score of 1 is given. The checks are added up for a possible score between 0 and 19. Also, the severity of symptoms in four categories unrelated to pain (including fatigue, cognitive problems, etc.) are rated on a scale from 0 to 3 for a maximum total score of 12. This is called the symptom severity score (SS).

Widespread Pain Index, Severity Score, and Diagnosis

Bot the WPI and the SS are considered together when making a fibromyalgia diagnosis. A patient satisfies the diagnostic criteria if one of the two situations are met and have been present for more than three months:

  • WPI score greater than 7 and SS score greater than 5
  • WPI score between 3 and 6 and SS score greater than 9

The new criteria have been tested with promising results. Researchers believe the new diagnostic process will catch more than 88% of fibromyalgia cases. Despite this success, the National Fibromyalgia Association (NFA) is concerned about eliminating the tender point test. An August 2010 statement released by the NFA called the recent ACR actions "unusually agressive," calling the tender point criterion a "defining feature of fibromyalgia."

The good news is that this kind of controversy usually means that progress is moving in the right direction. Regardless of which diagnostic criteria is used, if you suspect you may have fibromyalgia, it is a good idea to keep a pain diary, listing the daily locations and circumstances of your pain, its severity, and how long it lasts. This will help your doctor get a full and accurate picture of your symptoms.