Beckman Coulter Access Intact PTH Reagent, 100 determinations, 2 x 50 tests

Specifications

Brand: Access®

Manufacturer: Beckman Coulter

Country of Origin: United States

Application: Reagent

Number of Tests: 100 Tests

Sample Type: Blood Sample

Storage Requirements: Requires Refrigeration

Test Name: Intact Parathyroid Hormone (iPTH)

Test Type: Bone Metabolism Assay

Intended Use

The Access Intact PTH assay is a paramagnetic particle, chemiluminescent immunoassay for the quantitative determination of intact parathyroid hormone (parathyrin, PTH) levels in human serum and plasma using the Access Immunoassay Systems. It is indicated to aid in the differential diagnosis of hyperparathyroidism, hypoparathyroidism, or hypercalcemia of malignancy and can be used intraoperatively. Assay results should be used in conjunction with other clinical data to assist the clinician in making individual patient management decisions.

Summary and Explanation

Parathyroid hormone (PTH) is synthesized by the chief cells of the parathyroid glands and stored into dense neuroendocrine-type secretory granules, awaiting secretion. Intact PTH is an 84 amino acid polypeptide with a molecular mass of approximately 9.43 kilodaltons. After secretion PTH undergoes rapid proteolysis to generate various circulating C-terminal fragments. Some of these fragments re-enter the bloodstream and are cleared primarily by glomerular filtration, an important route for PTH clearance. The intact and biologically active peptide has a half-life in the circulation of less than 5 minutes.

PTH plays a crucial role in maintaining calcium homeostasis and its measurement is an important aid in the diagnosis of calcium related disorders. In healthy individuals, PTH secretion responds to small alterations in plasma ionized calcium concentration within seconds. Abnormally low ionized calcium concentrations trigger PTH secretion, whereas rising levels of extracellular calcium reduce PTH secretion through a negative feedback mechanism.

PTH regulates calcium levels by concerted effect on three principal organs: bone, intestinal mucosa and kidney. The effect of PTH on intestinal calcium is indirect, resulting from renal production of the intestinally active vitamin D metabolite, 1,25-dihydroxyvitamin D. In the kidney, PTH stimulates calcium reabsorption and inhibition of phosphate reabsorption from the renal tubules. Eventually PTH promotes osteoclastic bone resorption and release of calcium and phosphate from bone.