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Parathyroid Hormone (PTH) Plus Calcium

CPT: 82310; 83970
Updated on 10/18/2020
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Synonyms

  • PTH Intact

Special Instructions

This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.


Expected Turnaround Time

Within 1 day


Related Documents


Specimen Requirements


Specimen

Plasma and serum


Volume

1.5 mL plasma and 1 mL serum


Minimum Volume

0.7 mL plasma and 0.5 mL serum


Container

Lavender-top (EDTA) tube and red-top tube or gel-barrier tube


Collection

Transfer separated plasma to a plastic transport tube clearly labeled as EDTA plasma and maintain refrigerated temperature. If red-top tube is used, transfer serum to a plastic transport tube clearly labeled as serum.


Storage Instructions

Refrigerate


Stability Requirements

Temperature

Period

Room temperature

2 days (stability determined by manufacturer or literature reference)

Refrigerated

3 days (stability determined by manufacturer or literature reference)

Frozen

6 months (stability determined by manufacturer or literature reference)

Freeze/thaw cycles

Stable x1 (stability determined by manufacturer or literature reference)

Temperature

Period

Room temperature

3 days

Refrigerated

3 days

Frozen

14 days

Freeze/thaw cycles

Stable x3

Temperature

Period

Room temperature

2 days (stability determined by manufacturer or literature reference)

Refrigerated

3 days (stability determined by manufacturer or literature reference)

Frozen

6 months (stability determined by manufacturer or literature reference)

Freeze/thaw cycles

Stable x1 (stability determined by manufacturer or literature reference)


Causes for Rejection

Whole blood; plasma other than EDTA; hemolysis; room temperature serum sent for PTH intact


Test Details


Use

Differential diagnosis of hypercalcemia. PTH is an 84-amino acid peptide hormone that is responsible for the regulation of serum calcium levels within a narrow range.

PTH is secreted in response to decrease in serum calcium levels by increasing the renal reabsorption of calcium and lowering reabsorption of phosphorus. The measurement of PTH is a useful tool in the differential diagnosis and management of hypercalcemia. PTH assays can be of help in the diagnosis of tumors and hyperplasia of the parathyroid gland, as well as in localizing hyperfunctioning parathyroid tissue by assay of samples obtained via venous catheterization. The native or intact (1-84) PTH has a short half-life, measured in minutes, whereas the carboxy and midmolecule fragments, which are biologically inactive, have half-lives 10- to 20-fold higher. The high concentrations of biologically inactive fragments have interfered with use of C-terminal or midmolecule assays for evaluation of parathyroid function in patients with impaired renal function. Intact PTH assays provide a more accurate assessment of parathyroid patients including those with various renal diseases.


Methodology

Plasma: electrochemiluminescence immunoassay (ECLIA); serum: colorimetric


References

Brown RC, Aston JP, St John A, Woodhead JS. Comparison of poly- and monoclonal antibodies as labels in a two-site immunochemiluminometric assay for intact parathyroid hormone. J Immunol Methods. 1988 Apr 22; 109(1):139-144. 3356909
Endress DB, Villanueva R, Sharp CF Jr, Singer FR. Immunochemiluminometric and immunoradiometric determinations of intact and total immunoreactive parathyrin: Performance in the differential diagnosis of hypercalcemia and hyperparathyroidism. Clin Chem. 1991 Feb; 37(2):162-168. 1993319
Kao PC, van Hearden J, Grant CS, Klee GG, Khosia S. Clinical performance of parathyroid hormone immunometric assays. Mayo Clin Proc. 1992 Jul; 67(7):637-645. 1434896
Nussbaum SR, Zahradnik RJ, Lavigne JR, et al. Highly sensitive two-site immunoradiometric assay of parathyrin and its clinical utility in evaluating patients with hypercalcemia. Clin Chem. 1987 Aug; 33(8):1364-1367. 3608153

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
054601 Ca+PTH Intact 001016 Calcium mg/dL 17861-6
054601 Ca+PTH Intact 015610 PTH, Intact pg/mL 2731-8
054601 Ca+PTH Intact 004000 Intact PTH N/A

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