01 Oct
The major function of PTH is to maintain the serum total calcium concentration within a narrow range. The net effects of PTH are to increase the serum concentration of calcium and to decrease that of phosphate. The assay is useful in making the diagnosis of primary hyperparathyroidism, secondary hyperparathyroidism, and a differential diagnosis of hypercalcemia. The assay helps in distinguish hypercalcemia caused by either primary hyperparathyroidism or malignant disease.