[Bone and bone related biochemical examinations. Hormone and hormone related substances. Parathyroid hormone].

Parathyroid hormone (PTH) is the most important hormone to maintain serum calcium levels. PTH acts directly on bone by stimulating both bone resorption and bone formation with the reactive excess in the former when it acts continuously. PTH also acts on renal tubule to promote urinary excretion of phosphate as well as production active vitamin D (1,25 [OH] 2D) . 1,25 [OH] 2D has been also suggested to have some unique and direct action on the bone. Measurement of intact-PTH is essential for optimal management of bone abnormalities in patients with primary hyperparathyroidism, secondary hyperparathyroidism, and chronic kidney disease. The newer PTH assays ; whole-PTH and bio-intact PTH assay, use an antibody that binds the region including the first amino acid is present, making it specific for the complete molecule, (1-84)-PTH. Recently, a new molecular form of PTH has been reported, which cannot be detected by these newer PTH assays.