Calcium, Ionized

Test Code
306


CPT Codes
82330

Preferred Specimen
2 mL serum collected in a serum separator tube (SST)


Minimum Volume
0.6 mL


Instructions
Let clot and spin immediately with the cap on. Do not open tube. Ship the unopened gel barrier tube at room temperature. If submitting with any other assay, please submit a separate tube for this test.


Transport Temperature
Room temperature


Specimen Stability
Room temperature: 7 days
Refrigerated: 7 days
Frozen: Unacceptable


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Received frozen • Gross hemolysis • Grossly lipemic • Red-top tube (no gel)


Methodology
Ion Selective Electrode (ISE)

Setup Schedule
Set up: Daily evening; Report available: Next day


Reference Range
<8 Months  Not established
8 Months-10 Years 4.9-5.4 mg/dL
11-17 Years 4.8-5.3 mg/dL
Adult 4.8-5.6 mg/dL


Clinical Significance
Ionized calcium represents the true "bioavailable" calcium in the circulation. In situations where the total calcium is normal but does not fit the clinical picture, e.g. , hyperparathyroidism, a determination of the ionized calcium will, many times, show an elevation in the "bioavailable" calcium component. This may be due to alterations in protein concentrations, especially albumin, that binds most of the calcium in the circulation.


Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.