Results from red cell shape analyses of 623 blood samples from women residing in three countries are reported. Only 164 samples came from subjects with a confirmed physician¹s diagnosis of fibromyalgia (FM). Average ages of those with confirmed diagnoses were almost the same as those in the larger groups whose FM diagnostic situation is not known.

Mean percentages of the different cell types were remarkably similar between those with or without a known diagnosis and among the participants from the three countries. Increased flat cells was the most sig-nificant feature, and in the 5 groups the mean values ranged from 73.4% in the larger group of American women to 75.3% in the smaller group of English women. Because flat cells are poorly deformable and reduce the rate of capillary blood flow, this implies that the use of haemorheologic agents could be beneficial in those with FM.