Parathyroid Hormone, Serum
Use
This test is useful for the diagnosis and differential diagnosis of hypercalcemia, primary, secondary, and tertiary hyperparathyroidism, and hypoparathyroidism. It is also important for monitoring patients with kidney failure for potential renal osteodystrophy. The test measures the level of parathyroid hormone (PTH) in the serum, providing insights into calcium metabolism disorders often stemming from parathyroid gland dysfunction. PTH is responsible for maintaining calcium homeostasis through its actions on bone, kidney, and indirectly on the intestine.
Special Instructions
Patients should preferably fast for 12 hours before specimen collection. Additionally, for 12 hours prior, patients should avoid taking multivitamins or supplements containing biotin (vitamin B7). Perform test ordering using the provided forms if ordering electronically is not possible.
Limitations
Biotin concentrations up to 1200 ng/mL do not interfere with this assay, though caution is advised in cases of high-dose supplementation. The presence of certain antibodies in patients, such as human anti-mouse antibodies (HAMA), may interfere with immunoassays, potentially skewing results. It's important to interpret PTH results in conjunction with serum calcium and phosphorus levels, considering the complete clinical picture and any potential interfering substances. Antibody presence against streptavidin or ruthenium used in the assay may also interfere with results.
FDA ApprovedNew York Approved
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 2731-8
- 2731-8
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.75 mL
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial. Preferred collection in serum gel tube; red top acceptable.
Patient Preparation
12-hour fasting preferred; abstain from biotin for 12 hours prior.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 8 hours |
| Refrigerated | 72 hours |
| Frozen | 180 days |