To the Editors:

We are grateful to Dr. Toda for raising several important points. He is concerned that the 2010 preliminary criteria exclude patients with other disorders from the diagnosis of fibromyalgia. The 1990 criteria state that “… a diagnosis of fibromyalgia remains a valid construct irrespective of other diagnoses; ‘exclusionary tests’ such as radiographs, antinuclear antibody titers, T4 levels, etc. are not a requisite for diagnosis” (Wolfe F, Smythe HA, Yunus MB, Bennett RM, Bombardier C, Goldenberg DL, et al. The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee. Arthritis Rheum 1990;33:160–72).

The 2010 criteria do not change that position—fibromyalgia is not an exclusionary illness, and exclusionary tests are not needed. However, there are certain circumstances where exclusions (and tests) would make sense. As an example, we would want to exclude from a diagnosis of fibromyalgia patients with multiple bone metastases and anemia or with extreme hyperparathyroidism, and such patients might have generalized pain and fatigue. Every patient should have a diagnostic interview and examination. If the history and the clinical examination do not lead to suspicion of a somatic disease, no additional tests are needed. Only if there is another disease present that could explain the patient's pain that would ordinarily be attributed to fibromyalgia (as in metastatic cancer described above), should the diagnosis of fibromyalgia not be made. Although we used different wording in the 2010 criteria, the intent was exactly the same as in the 1990 criteria.

Dr. Toda also inquires about the problem of somatic symptoms: “How many symptoms are ‘few symptoms,’ ‘a moderate number of symptoms,’ and ‘a great deal of symptoms,’ respectively? Who decides the number of somatic symptoms in the new criteria? Do physicians decide it? Do patients decide it?”

The criteria ask physicians to interview patients to assess the extent of somatic symptoms. Based on the interview, the physician determines how to classify the number of symptoms. When physicians evaluate symptoms such as fatigue, cognitive problems, unrefreshed sleep (the other symptom items), and the extent of somatic symptoms, the physician brings to the evaluation experience with patients of all sorts, and expected norms for the various categories. The physician should use these skills and make the best judgment. In making these criteria, we recognized that there were many, often complex, evaluation questionnaires that could be used to provide more precise answers. But we also recognized that such questionnaires would never be used in primary care practice. So we chose questions that were suitable for clinical use, even though there were more exact questions that could have been used.

There is no specific number of symptoms for each category. It may be possible to determine the degree of somatic symptoms with a few questions in some patients and with many questions in other patients. The type and nature of the symptoms might be important. We rely on the experience and judgment of the physician.

Frederick Wolfe MD*, Daniel J. Clauw MD†, Mary-Ann Fitzcharles MB, ChB‡, Don L. Goldenberg MD§, Winfried Häuser MD¶, Robert S. Katz MD**, Philip Mease MD††, Anthony S. Russell MD‡‡, I. Jon Russell MD, PhD§§, John B. Winfield MD¶¶, * National Data Bank for Rheumatic Diseases and University of Kansas School of Medicine, Wichita, KS, † University of Michigan Medical School, Ann Arbor, MI, ‡ Montreal General Hospital and McGill University, Montreal, Quebec, Canada, § Newton-Wellesley Hospital and Tufts University School of Medicine, Boston, MA, ¶ Technische Universität München, Munich, Germany, ** Rush University Medical Center, Chicago, IL, †† Seattle Rheumatology Associates and Swedish Medical Center, Seattle, WA, ‡‡ University of Alberta, Edmonton, Alberta, Canada, §§ University of Texas Health Sciences Center, San Antonio, TX, ¶¶ University of North Carolina, Chapel Hill, NC.