Diagnosing fibromyalgia can be quite difficult. Not only are there no lab tests or imaging tests that can spot the disorder, there are also a number of other conditions that have similar symptoms. These include:
- Lyme disease
- certain types of cancer
- degenerative diseases of the spine
Tests can rule out many of these conditions, but doing so takes a lot of time, effort, and money.
According to the National Fibromyalgia Association (NFA), it takes an average of five years for a fibromyalgia patient to get a proper diagnosis.
Doctors use criteria set in 2010 by the American College of Rheumatology (ACR) to diagnose the syndrome. According to these rules, you have 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
- you have tenderness in at least 11 of the 18 tender points associated with fibromyalgia
Many doctors have criticized these criteria for diagnosing fibromyalgia. Since 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 consider any symptoms unrelated to pain, such as fatigue and depression.
Prior to the 2010 diagnostic criteria, the ACR report was from 1990. The 2010 update established new criteria for fibromyalgia. While the ACR still admits the importance of tender points, this new report decreases their diagnostic role. The ACR proposed a 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. Your doctor adds these checks for a score between 0 and 19.
Also, the severity of symptoms in four categories unrelated to pain (including fatigue, cognitive problems, etc.) is considered. These are rated on a scale from 0 to 3 for a total possible score of 12. This is called the symptom severity score (SS).
Diagnosis uses both the WPI and SS numbers. A patient has the disorder if one of the two following situations has 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 good results. Researchers believe the new diagnostic process will catch more than 88 percent of fibromyalgia cases.
Though the 2010 ACR update decreased the use of tender point exams, your doctor still might examine the 18 tender points associated with the disorder. Many doctors agree with the NFA that tender points are an important aspect of the syndrome.
In a tender point exam, your doctor will press on each point with his or her fingertip. They will use just enough pressure to whiten the nail bed, and ask if you feel any pain. The locations of these points include:
- between the shoulder blades
- tops of the shoulders
- back of the head
- front of the neck
- upper chest
- outer elbows
- upper hips
- inner knees
- sides of hips
Many conditions can cause symptoms similar to fibromyalgia. These must be ruled out in order to make an accurate diagnosis. Your doctor may use blood tests to rule out HIV, hypothyroidism, rheumatoid arthritis, and Lyme disease. You may undergo X-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI) for degenerative spinal diseases and many kinds of cancer. Your doctor may take tissue samples (biopsies) to test for cancer. Other tests, including sleep studies and psychological exams, may also be used.
Regardless of which diagnostic criteria are used, if you suspect you may have fibromyalgia, it’s a good idea to keep a pain diary listing:
- the daily locations of your pain
- traits of your pain
- its severity
- how long it lasts
This will help your doctor get a full and accurate picture of your symptoms.