Parathyroid Hormone-Related Peptide, Plasma
Use
This test is useful for aiding in the evaluation of individuals with hypercalcemia of unknown origin, as well as those with suspected humoral hypercalcemia of malignancy (HHM). It is not intended to exclude cancer or screen individuals with tumors for HHM. The test measures PTHrP, which is commonly elevated in several malignancies associated with HHM, including carcinomas of the breast, lung, and other organs, as well as neuroendocrine tumors. An elevated level suggests HHM as the cause for hypercalcemia, particularly in patients with a history of malignancy.
Special Instructions
The test should be performed with refrigerated centrifuge or in chilled centrifuge cups. Plasma should be aliquoted into a plastic vial and frozen immediately. Be aware that PTHrP can be elevated in pregnant and lactating women and in newborn infants, and nonmalignant conditions such as systemic lupus erythematosus.
Limitations
PTHrP measurements can be affected by the complexity of its isoforms and the absence of a common calibration standard. Results from different assays should not be compared. Some conditions, like heterophile antibody interference, may lead to false-positive results. Also, PTHrP assays may show false-low results due to the 'hook effect' at extremely high analyte concentrations.
New York Approved
Methodology
Immunoassay (Immunochemiluminometric Assay (ICMA))
Biomarkers
LOINC Codes
- 15087-0
- 15087-0
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.7 mL
Minimum Volume
0.25 mL
Container
Plastic vial
Collection Instructions
Centrifuge specimen in a refrigerated centrifuge or in chilled centrifuge cups. Aliquot plasma into plastic vial and freeze.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 30 days |