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HelpTest Code PTHRP Parathyroid Hormone-Related Peptide, Plasma
Additional Codes
PTH - Like Peptide
Reporting Name
PTH-Related PeptideUseful For
Aiding in the evaluation of individuals with hypercalcemia of unknown origin
Aiding in the evaluation of individuals with suspected humoral hypercalcemia of malignancy
The test should not be used to exclude cancer or screen individuals with tumors for humoral hypercalcemia of malignancy.
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Plasma EDTASpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Ice-cooled, lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.7 mL
Collection Instructions:
1. Centrifuge specimen in a refrigerated centrifuge or in chilled centrifuge cups.
2. Aliquot plasma into plastic vial and freeze.
Specimen Minimum Volume
0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma EDTA | Frozen | 30 days |
Reference Values
≤4.2 pmol/L
Reference values have not been established for patients younger than 1 year.
Day(s) Performed
Monday through Thursday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82397
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PTHRP | PTH-Related Peptide | 15087-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 81774 | PTH-Related Peptide | 15087-0 |
Interpretation
Depending on the patient population, up to 80% of individuals with malignant tumors and hypercalcemia will be suffering from humoral hypercalcemia of malignancy (HHM). Of these, 50% to 70% might have an elevated parathyroid hormone-related peptide (PTHrP) level. These patients will also usually show typical biochemical changes of excess parathyroid hormone (PTH)-receptor activation, namely, besides the hypercalcemia, they might have hypophosphatemia, hypercalcuria, hyperphosphaturia, and elevated serum alkaline phosphatase. Their PTH levels will typically be less than 30 pg/mL or undetectable.
In patients with biochemical findings that suggest, but do not prove, primary hyperparathyroidism (eg, hypercalcemia, but normal or near-normal serum phosphate, and a PTH level that is within the population reference range but above 30 pg/mL), HHM should be considered as a diagnostic possibility, particularly if the patient is an older adult, has a history of malignancy, or has risk factors for malignancy. An elevated PTHrP level in such a patient is highly suggestive of HHM as the cause for the hypercalcemia.
Clinical Reference
1. Donovan PJ, Achong N, Griffin K, Galligan J, Pretorius CJ, McLeod DS. PTHrP-mediated hypercalcemia: causes and survival in 138 patients. J Clin Endocrinol Metab. 2015;100(5):2024-2029
2. Goltzman D. Nonparathyroid hypercalcemia. Front Horm Res. 2019;51:77-90
3. Jacobs TP, Bilezikian JP. Clinical Review: Rare causes of hypercalcemia. J Clin Endocrinol Metab. 2005;90(11):6316-6322
4. Mundy GR, Edwards JR. PTH-related peptide (PTHrP) in hypercalcemia. J Am Soc Nephrol. 2008;19(4):672-675
Report Available
2 to 5 daysMethod Name
Immunochemiluminometric Assay (ICMA)
Forms
If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.