Test Catalog

Test Id : PTHRP

Parathyroid Hormone-Related Peptide, Plasma

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aiding in the evaluation of patients with hypercalcemia of unknown origin

 

Aiding in the evaluation of patients with suspected humoral hypercalcemia of malignancy

 

The test should not be used to exclude cancer or screen tumor patients for humoral hypercalcemia of malignancy.

Method Name
A short description of the method used to perform the test

Immunochemiluminometric Assay (ICMA)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

PTH-Related Peptide

Aliases
Lists additional common names for a test, as an aid in searching

Humoral Hypercalcemia of Malignancy Factor

Parathyroid Related Polypeptide

Parathyroid Related Protein

PRP

PTH Related Peptide

PTHRP, Plasma

PTH Related Protein

Parathyroid Hormone Related Peptide

Specimen Type
Describes the specimen type validated for testing

Plasma EDTA

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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.

Forms

If not ordering electronically, complete, print, and send a General Request (T239) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.25 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Plasma EDTA Frozen (preferred) 30 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aiding in the evaluation of patients with hypercalcemia of unknown origin

 

Aiding in the evaluation of patients with suspected humoral hypercalcemia of malignancy

 

The test should not be used to exclude cancer or screen tumor patients for humoral hypercalcemia of malignancy.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Parathyroid hormone-related peptide (PTHrP) exists in several isoforms, ranging in size from 60 to 173 amino acids, which are created by differential splicing and posttranslational processing by prohormone convertases. PTHrP is produced in low concentrations by virtually all tissues. The N-terminus and the secondary structure of multiple isoforms of PTHrP resemble parathyroid hormone (PTH), allowing PTHrP to bind to the same receptor as PTH.

 

The physiological role of PTHrP can be divided into 5 categories:

1) Transepithelial calcium transport, particularly in the kidney and mammary gland

2) Smooth muscle relaxation in the uterus, bladder, gastrointestinal tract, and arterial wall

3) Regulation of cellular proliferation

4) Cellular differentiation and apoptosis of multiple tissues

5) As an indispensable component of successful pregnancy and fetal development (embryonic gene deletion is lethal in mammals)

 

Hypercalcemia of malignancy (HHM) is a common complication of cancer. Elevations of PTHrP are the most common cause of malignancy-associated hypercalcemia. PTHrP leads to hypercalcemia by stimulating calcium resorption from bone and reabsorption in the kidneys. It also plays a significant function in osteolysis in bony metastases, particularly in breast cancer, and has been postulated to play a role in malignancy-associated cachexia through induction of orexigenic peptides.

 

Various malignancies secrete PTHrP resulting in HHM. PTHrP production is most commonly seen in carcinomas of breast, lung (squamous), head and neck (squamous), kidney, bladder, cervix, uterus, and ovary. Neuroendocrine tumors may also occasionally produce PTHrP. Most other carcinomas, sarcomas, and hematolymphoid malignancies only sporadically produce PTHrP, with the exception of T-cell lymphomas and myeloma. In HHM, the typical laboratory presentation includes elevated calcium and PTHrP, decreased PTH, and suppressed serum 1,25 dihydroxyvitamin D3 levels. Patients with HHM may have increased PTHrP values before treatment. PTHrP level decreases and PTH level increases, accompanied by decreased serum calcium values, are observed with successful treatment.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

< or =4.2 pmol/L

Interpretation
Provides information to assist in interpretation of the test results

Depending on the patient population, up to 80% of patients 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.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Parathyroid hormone-related peptide (PTHrP) can be elevated in pregnant and lactating women and in newborn infants. Nonmalignant conditions that have been described in association with elevated plasma PTHrP levels include systemic lupus erythematosus, HIV-associated lymphadenopathy, lymphedema of chest or pleural cavities, and with benign tumors of the ovary, kidney and the neuroendocrine system.

 

Because of the complexity of PTHrP isoforms, the differences between various PTHrP assays and the lack of a common calibration standard, PTHrP measurements performed with different assays cannot be compared easily.

 

The complex isoform mixture of PTHrP can occasionally lead to pronounced nonlinearity on dilution of patient specimens. In these situations an accurate measurement of PTHrP concentrations might be impossible.

 

Like all immunometric assays, PTHrP assays are susceptible to false-low results at extremely high analyte concentrations ("hooking") and to rare false-positive results due to heterophile antibody interference. Therefore, if test results are incongruent with the clinical picture, the laboratory should be contacted.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Donovan PJ, Achong N, Griffin K, et al: PTHrP-mediated hypercalcemia: causes and survival in 138 patients. J Clin Endocrinol Metab. 2015 May;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 Nov;90(11):6316-6322

4. Mundy GR, Edwards JR: PTH-related peptide (PTHrP) in hypercalcemia. J Am Soc Nephrol. 2008 Apr;19(4):672-675

Method Description
Describes how the test is performed and provides a method-specific reference

The parathyroid hormone-related peptide (PTHrP) assay is a plate-based chemiluminescent assay utilizing an anti-PTHrP rabbit-polyclonal antibody for capture and an acridinium ester anti-PTHrP goat-polyclonal antibody for detection. The assay targets 1-86 PTHrP.(Ashrafzadeh-Kian S, Bornhorst J, Algeciras-Schimnich A. Development of a PTHrP chemiluminescent immunoassay to assess humoral hypercalcemia of malignancy. Clin Biochem. 2022 Apr 14:S0009-9120(22)00103-5. doi: 10.1016/j.clinbiochem.2022.04.005)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Thursday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

2 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

3 months

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

82397

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
PTHRP PTH-Related Peptide 15087-0
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
81774 PTH-Related Peptide 15087-0

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports