Diagnostic Measures for Fibromyalgia


Fibromyalgia is a chronic pain syndrome that involves widespread muscle pain (myalgias) and joint pain (arthralgias). While there are no blood or imaging tests to diagnose fibromyalgia, it can be diagnosed by a clinician with guidelines outlined by the American College of Rheumatology. These guidelines include two main scoring measures to diagnose fibromyalgia: the Widespread Pain Index (WPI) and the Symptom Severity (SS) scale.

Widespread Pain Index

The Widespread Pain Index is a self-report measure that quantifies the extent of widespread pain throughout the body. It measures the presence of pain or tenderness in 19 specific areas of the body; each affected area receives one point. Areas of the body include the following:

  • Right and left jaw
  • Right and left shoulder girdle
  • Right and left upper arm
  • Right and left lower arm
  • Right and left hip/buttock
  • Right and left upper leg
  • Right and left lower leg
  • Upper and lower back
  • Neck
  • Chest
  • Abdomen

Symptom Severity scale

The Symptom Severity (SS) scale measures symptom severity on a scale from 0 to 12. It quantifies the severity of fatigue (scale of 0‒3), tiredness upon waking (scale of 0–3), and cognitive impairment (scale of 0‒3) over the preceding week. One point is also given for the presence of each of the following: headaches, lower abdominal pain, and depression.

The scale rates as follows:

  • 0 – No problem
  • 1 – A slight or mild problem (generally mild or intermittent)
  • 2 – A moderate or considerable problem (often present and/or at a moderate level)
  • 3 – A severe, continuous, life-disturbing problem

Diagnosis of fibromyalgia
A diagnosis of fibromyalgia may be given when:

  • Widespread pain has been present for 3 months or more.
  • Pain is on both the left and right side of the body and above and below the waist.
  • A WPI is ≥7 with an SS scale ≥5 OR a WPI range between 4‒6 with an SS scale ≥ 9.