[Biological exploration of Paget's disease].

The laboratory investigation of cases of Paget's disease has revealed results of three types :--small increases in the sedimentation rate, in the ceruloplasmin level, in the average corpuscule volume, and in uricaemia. These changes are of little practical value;--a considerable increase in the common stocks and in the turn-over of calcium, a frequently negative assessment with a parathyroid hormone level at the lower limit of normality. The levels of calcaemia and calciuria, little changed on average, may increase slightly after hospitalization. The use of these parameters is valuable but they are sometimes difficult to interpret;--an increase in the levels of alkaline phosphatases and of urinary hydroxyproline, in relation to the extent and the activity of the disease, and also of certain parameters of calcium-45 and of quantitative histology. A statistical study of the spontaneous evolution of hydroxyprolinuria in 50 patients with Paget's disease who were not treated for less than 3 years, allowed the authors to establish in what conditions a change induced by calcitonin or mithramycin is significant.