The most widely used tool for diagnosing FM is the American College of Rheumatology (ACR) criteria. In order to reach a diagnosis of fibromyalgia, the following 3 conditions must be met:[1]
- Widespread pain index (WPI) (the patient marks where their pain is located) ≥ 7 AND symptom severity scale (SSS) (the patient indicates how their symptoms interfere with their daily life) score ≥ 5 OR WPI of 4–6 AND SSS score ≥ 9.
- Generalized pain, defined as pain in at least 4 of 5 regions (left upper region, left lower region, right upper region, right lower region, and axial) must be present.
- Symptoms have been present for 3 months.
The ACTTION-APS Pain Taxonomy (AAPT) diagnostic criteria can also be used, albeit less frequently[2]:
- Pain in 6 or more of the following pain sites: head, left arm, right arm, chest, abdomen, upper back and spine, lower back and spine/buttocks, left leg, and right leg.
- Moderate to severe sleep problems OR fatigue.
- Pain and fatigue or sleep problems must be persistent for at least 3 months.
To date, there are no imaging or blood tests used for diagnosis.