 |
NAME | METHOD | REFERENCE RANGE | UNITS |
 |
Parathyroid Hormone, Intact | CEIA | 11.1 - 79.5 | pg/mL |
|
Calcium (Total) | S | < 2 years: 7.6 - 11
< 19 years: 8.4 - 10.5 >= 19 years: 8.7 - 10.4 |
mg/dL |
|
TYPE | VOLUME | TEMPERATURE | INSTRUCTIONS |
| PRIMARY | ||||
| 1 | Serum | 1.5 (1) mL | Frozen - 2 Month(s) | Split into 2 plastic vials before freezing. |
| PTH-Intact measures only the biologically active hormone and provides a more precise assessment of parathyroid function in patients with renal disease and those with age-related diseases of glomerular filtration. Intact PTH contains 84 amino acids with biological activity residing in the N-terminal third of the molecule. Therefore, synthetic PTH containing the first 34 amino acids has full biological activity. An inverse relationship exists between PTH secretion and free calcium, since free calcium in blood and intracellular fluid is the primary physiological regulator of PTH secretion. PTH influences both calcium and phosphate homeostasis through actions on bone, kidney, and (indirectly) on 1,25 hydroxyvitamin D. In the kidneys, PTH increases calcium absorption in the distal tubule of the nephron. PTH decreases reabsorption of phosphate by the proximal tubule and stimulates the production of 1,25 hydroxyvitamin D, which stimulates the intestinal absorption of both calcium and phosphate. Generally less than 5 to 25% of total immunoreactive PTH is intact hormone. The remaining 75 to 95% is inactive midregion/carboxyl fragments. In hypercalcemia, secretion of these inactive forms persist, while secretion of intact hormone is greatly reduced or absent. |
