Quantitative sensory testing in fibromyalgia patients and in healthy subjects: identification of subgroups. Clin J Pain 2001 Dec;17(4):316-22 Hurtig IM, Raak RI, Kendall SA, Gerdle B, Wahren LK. Department of Medicine and Care, Pharmacology, Faculty of Health Sciences, Linkoping, Sweden. mailto:ingrid@hurtig@far.liu.se PMID: 11783811 OBJECTIVE: To determine perception and pain thresholds in patients with fibromyalgia syndrome and in healthy controls, and to investigate whether patients with fibromyalgia syndrome can be grouped with respect to thermal hyperalgesia and whether these subgroups differ from healthy controls and in clinical appearance. DESIGN: The authors conducted a quasi-experimental clinical study. SUBJECTS: Twenty-nine women patients with fibromyalgia syndrome and 21 healthy pain-free age-matched women participated in the study. METHODS: Quantitative sensory testing using a Thermotest instrument was performed on the dorsum of the left hand. Sleep and pain intensity were rated using visual analog scales. RESULTS: Cold and heat pain but not perception thresholds differed significantly between patients with fibromyalgia syndrome and healthy subjects. Based on thermal pain thresholds, two subgroups could be identified in fibromyalgia syndrome using cluster analysis. CONCLUSION: Patients with fibromyalgia syndrome were subgrouped by quantitative sensory testing (i.e., thermal pain thresholds). Subgroups show clinical differences in pain intensities, number of tender points, and sleep quality. Cold pain threshold was especially linked to these clinical aspects.