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Calcium, Ionized (serum) [306]
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Test Code
IOCAL
Alias/See Also
306;
CA++;
Calcium Free;
Free CA;
Free Calcium;
Ionized Calcium
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.
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
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 Specific Electrode (ISE)
Setup Schedule
Set up: Daily; Report available: 1-2 days
Reference Range
| <8 Months | 5.3-6.3 mg/dL |
| 8-11 Months | 5.2-6.1 mg/dL |
| 1 Year | 5.1-6.0 mg/dL |
| 2 Years | 4.9-5.8 mg/dL |
| 3 Years | 4.9-5.7 mg/dL |
| 4-6 Years | 4.8-5.7 mg/dL |
| 7-12 Years | 4.8-5.6 mg/dL |
| 13-17 Years | 4.8-5.5 mg/dL |
| 18-89 Years | 4.7-5.5 mg/dL |
| ≥90 Years | 4.5-5.5 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: October 30, 2023
