Use of the American College of Rheumatology classification criteria for the clinical diagnosis of fibromyalgia syndrome (FMS) is under debate. The Regional Pain Scale (RPS) had been developed for the diagnosis of FMS in clinical practice and in survey settings (survey criteria of FMS). So far a German version has not been validated.
A total of 216 patients with FMS, 53 with active rheumatoid arthritis (RA) and 60 with depressive disorder, recruited from clinical institutions completed the RPS. Forty-three patients with FMS filled in the RPS within 8 weeks a second time.
The intraclass coefficient of FMS diagnosis after 8 weeks was 0.78 (test-retest reliability). The 7-day interval of pain was criticized by physicians. The absence of some articular pain regions was criticized by patients (face validity). The concordance of FMS diagnoses to survey and ACR criteria was 84.7% (+/-1.1); 45.3% of the patients with RA and 38.3% of the patients with depressive disorder met the survey criteria of FMS (discriminant validity).
The RPS has good reliability and convergent validity, but limited discriminant validity. The RPS is suited as a screening instrument for the diagnosis of FMS in clinical practice.