PTH and hypophosphatemia: The biochemical profile of PHPT is classically characterized by elevated serum intact parathyroid hormone (PTH) levels coupled with hypercalcemia and slight or mild hypophosphatemia (with or without hypercalciuria).1, 3 Thus, the diagnosis of PHPT is based on the combination of hypercalcemia and elevated PTH.3 However, not all PHPT patients exhibit this biochemical pattern.