Calcium, Ionized
Also known as: CA++, CA, Ionized, Calcium Free, Calcium
Use
Ionized calcium represents the true “bioavailable” calcium in the circulation. It may better reflect the patient’s physiologic calcium status in situations where total calcium appears normal but is inconsistent with clinical findings—such as in hyperparathyroidism or when protein (especially albumin) concentrations alter bound calcium levels.
Special Instructions
Let clot and spin immediately with the cap on; do not open the tube. Ship the unopened gel barrier tube at room temperature. If submitting with any other assay, submit a separate tube for this test.
Limitations
Not provided.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 17863-2
Result Turnaround Time
4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
0.6 mL
Container
Gel barrier tube (SST)
Collection Instructions
Let clot and spin immediately with cap on; do not open tube
Storage Instructions
Ship at room temperature
Causes for Rejection
Gross hemolysis; grossly lipemic; received frozen; red‑top tube (no gel)
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 7 days |
| Frozen | Unacceptable |
Other tests from different labs that may be relevant