| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Parathormone, Intact
Test CodeAlias/See Also
CPT Codes
83970
Preferred Specimen
Green
Minimum Volume
Other Acceptable Specimens
Transport Container
Serum (gold top), Lithium Heparin Plasma (green top) or EDTA (purple top) Tube
Transport Temperature
Specimen Stability
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Methodology
Chemiluminescence
Setup Schedule
Daily upon receipt
Report Available
Reference Range
7.5 - 53.5 pg/mL
Clinical Significance
Parathyroid hormone (PTH) is a single chain 84 amino acid polypeptide produced by the parathyroid gland. After PTH is secreted into the blood stream it undergoes extensive proteolysis to generate various fragments. In contrast to its degradation products, the concentration of Intact PTH is relatively independent of glomerular filtration rate and reflects the biologically active portion of the hormone.
The primary role of PTH is to maintain calcium homeostasis via its interaction with calcitonin. PTH measurement is an important aid in the diagnosis of disorders of calcium metabolism. PTH synthesis and secretion are triggered rapidly by low concentrations of ionized calcium (Cai). The biological activities of PTH are to increase absorption of dietary calcium, decrease renal clearance and mobilize skeletal calcium stores. Abnormally high Cai concentrations suppress secretion of PTH. In conjunction with serum calcium levels, the PTH assay may be used as an aid in the differential diagnosis of hypercalcemia, hypocalcemia and parathyroid disorders. PTH determination is important in monitoring dialysis patients to manage renal osteodystrophy.
Guidelines from the National Academy of Clinical Biochemistry recommend the use of intraoperative parathyroid hormone testing for patients during surgery for hyperparathyroidism, especially in minimally invasive or directed procedures, as well as for patients undergoing reoperation. For patients undergoing parathyroidectomy it is recommended that preoperative and pre-excision samples are taken. Samples should also be drawn at 5 and 10 minutes post resection and a > 50%reduction in PTH levels from the highest baseline may be used as criteria for surgical success.