Preferred Specimen(s) 1.5 mL plasma collected in a PTH-related protein (special collection) tube
Instructions Store cocktail tube in the freezer at -20°C (tubes can be stored for up to one year). The cocktail tube is a heparin tube with protease inhibitor (aprotinin, leupeptin & blue dye) added (glass or plastics collection tubes are acceptable). Prior to drawing samples, place PTHrP cocktail tubes on ice. Collect the whole blood into a syringe and transfer the sample into the cocktail tube. Alternatively, if a syringe is not available, collect the blood in a plain red-top tube and immediately transfer the sample into the cold cocktail tube. Mix thoroughly by inversion. Immediately separate the plasma from the cells in a refrigerated centrifuge and transfer to a plastic test tube. Freeze immediately at -20°C or colder. If a refrigerated centrifuge is not available, chill the tubes and the centrifuge tube holders for 5 minutes in an ice lorry. Ship frozen.
Transport Container Plastic screw-cap vial
Transport Temperature Frozen
Reject Criteria
- Received room temperature
- Received refrigerated
Methodology Immunoassay
Clinical Significance Parathyroid hormone-related peptide (PTH-rP) is structurally and functionally similar to human parathyroid hormone (HPTH). Hypercalcemia of malignancy is due either to local osteolysis at the site of bone metastases or to PTH-rP production by the malignant cells.