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PTH, Intact (ICMA) and Ionized Calcium
Test Code36736
CPT Codes
82310, 82330, 83970
Includes
PTH, Intact
Calcium
Calcium, Ionized
Calcium
Calcium, Ionized
Preferred Specimen
PTH, Intact: 1.5 mL plasma collected in an EDTA (lavender-top) tube
Calcium: 1 mL serum
Ionized Calcium: 2 mL serum collected in a gel barrier tube
Calcium: 1 mL serum
Ionized Calcium: 2 mL serum collected in a gel barrier tube
Minimum Volume
1 mL EDTA plasma for PTH, Intact • 0.5 mL serum for Calcium • 0.6 mL serum for Ionized Calcium
Other Acceptable Specimens
2 mL (1 mL minimum) frozen serum for PTH, Intact
Instructions
Submit three tubes.
PTH, Intact: Centrifuge and transfer plasma to a transport tube. Label as PLASMA for the PTH, Intact.
Ionized Calcium: Let clot and spin immediately with the cap on. Ship the unopened gel barrier tube at room temperature. Do not open.
PTH, Intact: Centrifuge and transfer plasma to a transport tube. Label as PLASMA for the PTH, Intact.
Ionized Calcium: Let clot and spin immediately with the cap on. Ship the unopened gel barrier tube at room temperature. Do not open.
Transport Temperature
PTH, Intact: Frozen
Calcium: Room temperature
Ionized Calcium: Room temperature
Calcium: Room temperature
Ionized Calcium: Room temperature
Specimen Stability
EDTA plasma for PTH, Intact
Room temperature: 48 hours
Refrigerated: 72 hours
Frozen: 6 months
Serum for PTH, Intact
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 6 months
Serum for Calcium
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Serum for Ionized Calcium
Room temperature: 7 days
Refrigerated: 7 days
Frozen: Unacceptable
Room temperature: 48 hours
Refrigerated: 72 hours
Frozen: 6 months
Serum for PTH, Intact
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 6 months
Serum for Calcium
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Serum for Ionized Calcium
Room temperature: 7 days
Refrigerated: 7 days
Frozen: Unacceptable
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Grossly lipemic • Plasma in sodium heparin (green-top) tube or lithium heparin (green-top) tube
Methodology
PTH: Immunoassay (IA) • Calcium: Spectrophotometry (SP) • Ionized Calcium: Ion Specific Electrode (ISE)
Setup Schedule
Set up: Mon-Sat: Report available: 2-4 days
Clinical Significance
The assay is useful in making the diagnosis of primary hyperparathyroidism, secondary hyperparathyroidism, and a differential diagnosis of hypercalcemia. The assay helps in distinguishing hypercalcemia caused by either primary hyperparathyroidism or malignant disease.