An imbalance of the trace element status in human tissues and body fluids has been suggested as a contributing factor for the development of fibromyalgia (FM). The study comprised 38 females with defined fibrornyalgia (FM) according to generally accepted criteria from the American College of Rheumatology (ACR). They were compared with 41 females matched for age and Geographic location. The concentrations of about 30 trace element and ions were determined in whole blood, urine and drinking water of all participants by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectroscopy (ICP-OES). Significantly higher concentrations in whole blood of Cd, Co, Cu, Fe, Se, Sri and Zn (p <= 0.046) were observed in the FM-cases in comparison with the referents. A different pattern was noted in urine with increased urinary excretion of Ag (p=0.003) among the I'M-patients. The urinary excretion of the other elements were of the same magnitude or slightly lower in FM-cases as compared to referents. As nearly all of the concentrations of the studied elements in blood and urine were within reported reference intervals in non-occupationally exposed populations, the clinical significance of the differences observed seems to be limited. The element concentrations of the studied elements in drinking water were within present national and international guideline values (EU, WHO) and the concentrations of potentially toxic metals such as e.g. Cd, Hg and Pb were low. In conclusion, the present investigation could not demonstrate abnormal levels of trace elements in blood or urine of FM-patients and, thus, does not support the hypothesis that trace element abnormalities play a significant role in the development of FM. (C) 2007 Elsevier B.V. All rights reserved.