Question-based Review on Differential Diagnosis of Hypercalcemia (Pseudohypercalcemia, PTH-dependent vs PTH-independent Hypercalcemia) and Hypocalcemia; Vitamin D abnormalities, Abnormalities of Phosphate. Also discussed: Workup & Management of Humoral Hypercalcemia of Malignancy, Familial Hypocalciuric Hypercalcemia, Pseudohypoparathyroidism, True Hypoparathyroidism, Primary, 2ndary and tertiary hyperparathyroidism, Medications Side-Effects causing abnormalities of Ca & P.