It is now generally recognized that the determination of serum calcium, inorganic phosphorus and phosphatase activity, in conjunction with clinical and roentgenologic study, may provide evidence of value in the differential diagnosis of certain diseases of bone. It is becoming increasingly evident, however, that for adequate interpretation of the variations in these constituents of the blood, particularly as regards their significance with respect to the underlying physiologic mechanisms involved, more data are desirable. This study is concerned with a review and appraisal of the available relevant but scattered data relating to hyperparathyroidism, Paget's disease, multiple myeloma and neoplastic disease of the bones. Additional observations on personally studied cases are presented.
METHODS
Twenty cubic centimeters of venous blood obtained from patients while fasting was transferred to a 25 cc. pyrex centrifuge tube, allowed to clot for one-half hour and then centrifugated for from five to ten minutes at 1,000 revolutions per