Calcium, Ionized [306]

Message
For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.


Test Code
IOCAL


Alias/See Also
306;
CA++;
Calcium Free;
Free CA;
Free Calcium;
Ionized Calcium


CPT Codes
82330

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


Minimum Volume
0.6 mL


Instructions
Collect blood (2 mL serum) in a gel barrier tube. Let clot and spin immediately with cap on. Do not open tube. Ship the unopened gel barrier tube at room temperature. Do not freeze.
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


Last Updated: November 24, 2021


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.