Specimen Information

Type

Lavender, EDTA

Volume

1 ml EDTA Plasma and 1 ml Serum

Transport Info

Refrigerated
48 hour stability

Fasting Required?

False

Clinical Significance

An important aid in the diagnosis of calcium metabolism disorders.
The parathyroid hormone (PTH) is an 84 amino acid peptide produced by the parathyroid gland. Since the PTH molecule undergoes extensive proteolytic modifications, human serum contains both the intact molecule and several fragments of the peptide. The ratios of intact hormone to peptide fragments may vary from individual as well as between patients with hyperparathyroidism or chronic renal failure.Since PTH maintains calcium homeostasis, its measurement is an important aid in the diagnosis of calcium metabolism disorders. Decreased serum calcium levels result in increased PTH secretion, causing increased absorption of dietary calcium, decreased renal clearance and mobilization of skeletal calcium stores. In conjunction with calcium levels, PTH quantitation can help distinguish between normal patients and patients with hyperparathyroidism, hypoparathyroidism or hypercalcemia of malignancy. Free-labeled antibody is separated from the labeled antibody bound to the magnetic particles by aspiration of the reaction mixture and subsequent washing. The wells containing the washed magnetic particles are transported into the system luminometer, which automatically injects Trigger 1 and Trigger 2, initiating the chemiluminescence reaction. The light is quantitated by the luminometer and expressed as RLU. The amount of bound-labeled antibody is directly proportional to the concentration of intact PTH in the sample.