The measurement of calciotropic hormones may be useful in metabolic bone disease. Assays of intact parathyroid hormone are essential to differentiate between primary hyperparathyroidism and nonparathyroid-mediated hypercalcemia. Vitamin D status is best assessed by measuring serum 25(OH)D. Concentrations of calciotropic hormones should be measured in osteoporotic patients if the degree of osteopenia does not correlate with the risk factors. The decrease in circulating parathyroid hormone in osteoporotic patients treated with vitamin D reflects the success of the vitamin D treatment. Parathyroid hormone is also a potential anabolic agent.