<prompt> Renal osteodystrophy differs from nutritional osteomalacia by having___.Increased phosphatesIncreased calciumDecreased calciumNone of the above  <response>: Ans. a Increased phosphates Ref. H-17th2694In addition to measuring serum calcium, it is useful to determine albumin, phosphorus, and magnesium levels. As for the evaluation of hypercalcemia, determining the PTH level is central to the evaluation of hypocalcemia. A suppressed or inappropriately low PTH level in the setting of hypocalcemia establishes absent or reduced PTH secretion hypopar- athyroidism as the cause of the hypocalcemia. Further history will often elicit the underlying cause i.e., parathyroid agenesis vs. destruction. By contrast, an elevated PTH level secondary hyperparathyroidism should direct attention to the vitamin D axis as the cause of the hypocalcemia. Nutritional vitamin D deficiency is best assessed by obtaining serum 25-hydroxyvitamin D levels, which reflect vitamin D stores.PRINCIPAL SYSTEMIC MANIFESTATIONS OF CHRONIC RENAL FAILURE AND UREMIAFluid and ElectrolytesCalcium Phosphate and Bone Dehydration Hyperphosphatemia Edema Hypocalcemia Hyperkalemia Secondary hyperparathyroidism Metabolic acidosis Renal osteodystrophy 