1.Widespread pain index (
WPI) 7 and symptom severity (SS) scale score 5 or WPI 3–6 and SS scale score 9.
2.Symptoms have been present at a similar level for at least 3 months.
3.The patient does not have a disorder that would otherwise explain the pain.
Reference:
Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Katz RS, Mease P, Russell AS, Russell IJ, Winfield JB, Yunus MB.