Parathyroid Hormone-Related Peptide (PTHrP) by LC-MS/MS, Plasma

Casandra

Casandra Test Code AR70708Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 2010677CPT Code 82542

Parathyroid Hormone-Related Peptide (PTHrP) by LC-MS/MS, Plasma

Also known as: PTHRP

Clinical Use

Order Test

Use

This test aids in the evaluation of unexplained hypercalcemia, particularly in the context of suspected hypercalcemia of malignancy. It is specifically designed to measure amino (N)- and carboxy (C)-terminus PTHrP fragments. This feature makes it especially useful because it does not get affected by these fragments often produced by patients with renal insufficiency. This specific aspect enhances its reliability in clinical scenarios where hypercalcemia's etiology needs precise elucidation, especially in the presence of possible malignant processes.

Special Instructions

A specific Protease Inhibitor tube (PPACK; Phe-Pro-Arg-chloromethylketone) is required for collection and is available through ARUP supply with reference #49662. Collection should employ a winged set. Once collected, mix well and separate from cells within an hour, transferring 1.5 mL plasma to an ARUP standard transport tube, with a minimum required volume of 0.7 mL. The specimen must be stored and transported frozen, as specimens are unacceptable under ambient or refrigerated conditions.

Limitations

The test has not been cleared or approved by the U.S. Food and Drug Administration but is performed in a CLIA-certified laboratory, maintaining high standards suitable for clinical purposes. While the test does not consider amino- and carboxy-terminal fragments as interfering substances, it may be limited if gross hemolysis occurs in the sample. Specimens that have not been frozen or are not appropriately separated within the specified time may also not yield accurate results.

Test Details

New York Approved

Methodology

Mass Spectrometry

Biomarkers

Parathyroid Hormone-Related Peptide

Protein

Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Result Codes

15087-0

Result Turnaround Time

2-6 days

Specimen

Plasma

Volume

1.5 mL

Minimum Volume

0.7 mL

Container

ARUP Standard Transport Tube

Collection Instructions

Collect using Protease Inhibitor tube (PPACK; Phe-Pro-Arg-chloromethylketone). Use a winged collection set. Mix well and separate from cells within 1 hour of collection.