Diagnostic Criteria for Fibromyalgia

Description of Current Criteria

The diagnosis of fibromyalgia has evolved considerably since it was formally recognized by the American College of Rheumatology (ACR) in 1990. Currently, diagnostic criteria focus on the evaluation of two key components: the Widespread Pain Index (WPI) and the Symptom Severity Scale (SSS).

The Widespread Pain Index (WPI) assesses the distribution of pain across different areas of the body. This index is calculated by summing the areas of the body where the patient has experienced pain in the past week, with a maximum of 19 possible areas. On the other hand, the Symptom Severity Scale (SSS) is composed of two parts: the first measures the severity of fatigue, unrefreshing sleep, and cognitive problems, while the second assesses other somatic symptoms such as headaches, depression, and gastrointestinal problems.

To meet the current ACR diagnostic criteria, a patient must meet the following requirements (Wolfe et al., 2016):

1. Generalized Pain: The patient must have pain in at least 7 of the 19 areas evaluated by the IDG.
2. Symptom Severity: The GSI must be at least 5 points. Alternatively, a GSI of 3 to 6 combined with an GSI of at least 9 points may also meet the criteria.
3. Duration of symptoms: Symptoms must have been present consistently for at least three months.
4. Absence of Other Disorders: There should be no other condition that can explain the patient’s pain and symptoms.

Evolution of Diagnostic Criteria

Over the years, the diagnostic criteria for fibromyalgia have undergone several changes. The first criteria established by the ACR in 1990 focused on tenderness at specific points known as “trigger points.” According to these criteria, a patient must have pain in at least 11 of the 18 trigger points during a physical examination.

However, these criteria proved to be limiting, as they failed to consider other important symptoms such as fatigue and cognitive impairments. Furthermore, variability in trigger point assessment among clinicians posed problems with diagnostic consistency. For these reasons, in 2010 and 2016, the ACR revised the criteria to incorporate a more comprehensive, less trigger point-dependent assessment (Wolfe et al., 2010; Wolfe et al., 2016).

The revised 2010 and 2016 criteria introduced the use of the GDI and GSS to assess symptom distribution and severity. These new criteria allow for a more holistic assessment of fibromyalgia and recognize the wide range of symptoms that may be present in patients.

In addition to the ACR criteria, other diagnostic approaches have been proposed. For example, a study by Arnold et al. (2019) suggested that including laboratory tests assessing inflammatory biomarkers could improve diagnostic accuracy. However, the implementation of these approaches is still under investigation and has not been widely adopted.

Bibliographic References.

• Wolfe, F., Clauw, D.J., Fitzcharles, M.A., Goldenberg, D.L., Katz, R.S., Mease, P., & Walitt, B. (2016). Revisions to the 2010/2011 diagnostic criteria for fibromyalgia. Arthritis and Rheumatism Seminars, 46(3), 319–329.
• Wolfe, F., Clauw, D.J., Fitzcharles, M.A., Goldenberg, D.L., Katz, R.S., Mease, P.J., & Walitt, B. (2010). American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and symptom severity measure. Arthritis Care & Research, 62(5), 600–610.
• Arnold, L.M., Clauw, D.J., McCarberg, B.H., & FibroCollaborative. (2019). Improving the recognition and diagnosis of fibromyalgia. Mayo Clinic Proceedings, 84(5), 451–459.

• Häuser, W., Fitzcharles, M.A., & Sommer, C. (2017). Etiology and pathophysiology of fibromyalgia syndrome and related disorders. Best Practice & Research Clinical Rheumatology, 25(2), 141–150.
• Sarzi-Puttini, P., Giorgi, V., Atzeni, F., Gorla, R., Marchesoni, A., Turiel, M., & Furlan, R. (2020). Fibromyalgia: an update on clinical features, etiopathogenesis, and treatment. Nature Reviews Rheumatology, 16, 645–660.