PTH and chronic kidney disease: According to Kidney Disease Improving Global Outcomes (KDIGO) guidelines, CKD–MBD is a systemic disorder of mineral and bone metabolism due to CKD manifested by either one or a combination of the following: (1) abnormalities of calcium, phosphorus, intact parathyroid hormone (PTH), or vitamin D metabolism; (2) abnormalities in bone turnover, mineralization, volume, linear growth, or strength; or (3) vascular or other soft-tissue calcification.