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Test Code PTH Parathyroid Hormone (PTH), Intact

Additional Codes

Epic: LAB108

Specimen Required

Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 3.0 mL
Collection Instructions: Centrifuge and separate cells after clot formation and within 4 hours of collection.  Remove serum if testing will be delayed more than 8 hours.

Specimen Minimum Volume

0.5 mL

Specimen Stability

Room Temperature: Unacceptable
Refrigerated (on gel): 8 hours
Refrigerated (off gel): 48 hours
Frozen: 6 months 

Clinical Significance

PTH is secreted by the parathyroid gland. The concentration of intact PTH is independent of the GFR and reflects the biologically active portion of the hormone. The primary role of PTH is to regulate blood Ca levels. The biological activity of PTH is to increase absorption of dietary calcium, decrease renal clearance and mobilize skeletal calcium stores. High calcium concentrations suppress secretion of PTH.
In conjunction with serum calcium levels, PTH is used as an aid in the differential diagnosis of hypercalcemia, hypocalcemia, and parathyroid disease. PTH determination is important in monitoring dialysis patients to manage renal osteodystrophy.
 

Reference Range

See Laboratory Report

Rejection Due To

Samples stored on gel >8 hours, unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements.

Day(s) and Time(s) Performed

Daily

Report Available

Same day

Method Name

Chemiluminescent microparticle immunoassay (CMIA)

LOINC

2731-8

Limitations

If the iPTH results are inconsistent with clinical evidence, additional testing is suggested to confirm the result.
Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassay.
This assay has not been clinically validated for intraoperative use.