Table 1.

Differences between the ACR 1990 1 and the revised ACR 2010 9 criteria for FM

1990	2010
History of widespread pain	WPI ≥ 7 and SS ≥ 5 OR WPI 3–6 and SS ≥ 9
Pain of ≥ 3 months’ duration	Symptoms have been present at a similar level for ≥ 3 months
Pain in 11 of 18 tender points on digital palpation	Patient does not have a disorder that would otherwise explain the pain
Definitions
Widespread pain Pain on left side of body, right side of body, above waist, below waist and axial skeletal pain	WPI score The number of areas in which patient has had pain over the last week (six lower extremities, six upper extremities, seven axial skeleton) Final score: between 0 and 19
Tender points (all bilateral) Occiput, low cervical, trapezius, supraspinatus, second rib, lateral epicondyle, gluteal, greater trochanter, knee	SS score The sum of severity of fatigue, waking unrefreshed and cognitive symptoms, plus the severity of general somatic symptoms Each symptom is rated on a scale of 0–3, where 0 = no symptoms/problem and 3 = severe symptoms/problems Final score: between 0 and 12

ACR, American College of Rheumatology; FM, fibromyalgia; SS, symptom severity; WPI, Widespread Pain Index.