At this time, there is no specific test that can be used to diagnose fibromyalgia. The syndrome is usually diagnosed by documenting the patient’s medical history, ruling out disorders and diseases that may be mimicking or exacerbating fibromyalgia, and by utilising the criteria developed by the American College of Rheumatology (ACR) in 1990. These were substantially revised in 2010 with changes made to include impact assessment of the widespread pain. A patient satisfies diagnostic criteria for fibromyalgia if the following three conditions are met:
- Widespread pain index (WPI) ≥ 7 and symptom severity (SS) scale score ≥ 5 or WPI 3–6 and SS scale score ≥ 9.
- Symptoms have been present at a similar level for at least 3 months.
- The patient does not have a disorder that would otherwise explain the pain.
1) WPI: note the number areas in which the patient has had pain over the last week. In how many areas has the patient had pain? Score will be between 0 and 19.
- Shoulder girdle, left; Hip (buttock, trochanter), left; Jaw, left; Upper back
- Shoulder girdle, right; Hip (buttock, trochanter), right; Jaw, right; Lower back
- Upper arm, left; Upper leg, left; Chest; Neck
- Upper arm, right; Upper leg, right; Abdomen
- Lower arm, left; Lower leg, left
- Lower arm, right; Lower leg, right
2) SS scale score:
- Waking unrefreshed
- Cognitive symptoms
For the each of the 3 symptoms above, indicate the level of severity over the past week using the following scale:
0 = no problem
1 = slight or mild problems, generally mild or intermittent
2 = moderate, considerable problems, often present and/or at a moderate level
3 = severe: pervasive, continuous, life-disturbing problems
Considering somatic symptoms in general, indicate whether the patient has:*
0 = no symptoms
1 = few symptoms
2 = a moderate number of symptoms
3 = a great deal of symptoms
The SS scale score is the sum of the severity of the 3 symptoms (fatigue, waking unrefreshed, cognitive symptoms) plus the extent (severity) of somatic symptoms in general. The final score is between 0 and 12.
Because a patient’s symptoms may vary and may come and go, a person may not meet the criteria at the time they are initially tested. Doctors generally consider the results of this evaluation in conjunction with other findings.
Laboratory tests can be useful to help diagnose conditions with symptoms similar to fibromyalgia and to identify disorders that may be coexisting with fibromyalgia, such as rheumatoid arthritis, Sjögren’s syndrome, thyroid disease, and lupus. It is not usually cost effective or necessary to do extensive screening. General tests that may be ordered include:
Other specific tests may be ordered to rule out diseases that mimic fibromyalgia based on the patient's symptoms and on the findings of these general screening tests. It should be noted that any abnormal laboratory test results are usually due to something other than fibromyalgia.
Some very specialised laboratory tests, such as the measurement of Substance P (a that signals the brain to register pain), may be used in a research setting to attempt to better understand the cause and course of fibromyalgia, but they are not considered clinically useful at this time.
Occasionally, an imaging scan may be ordered to help rule out a disorder that is causing symptoms similar to fibromyalgia, such as an (magnetic resonance imaging) to help identify multiple sclerosis.
Last Review Date: August 11, 2014