PTH and secondary hyperparathyroidism: Secondary hyperparathyroidism (SHPT) is a major and common complication that develops in chronic kidney disease (CKD) patients undergoing hemodialysis (HD).[1] SHPT is a maladaptive response triggered by hypocalcemia, hyperphosphatemia, and active vitamin D defciency, the increased level of fibroblast growth factor 23 (FGF-23).[2] which in turn causes parathyroid cells to overproduce parathyroid hormone (PTH).