Laboratory Evaluation of Paget's Disease	

	There is no abnormality in calcium or phosphate homeostasis. There is, however, a marked increase in urinary hydroxyproline (hydroxyproline is an amino acid that is almost unique to collagen, and urinary excretion reflects increased bone turnover) and serum alkaline phosphatase. Alkaline phosphatase is an enzyme that is produced by osteoblasts and its increase reflects increased osteoblastic activity.