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Calcium Ionized

Order Code CH392
Turnaround Time 24 hours
Specimen Requirements
Specimen Source
Transport Container
(Specimen Container)

SST (Tiger Top)

Preferred Specimens
Collection Instructions
(Transport Temperature)
Transport Refrigerated (cold packs)
Specimen Stability
Temperature Period
Room temperature Unacceptable
Refrigerated 7 days
Frozen Unacceptable
Reject Criteria

Gross hemolysis
Grossly lipemic
Received frozen
Uncapped tube

Special Instructions

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

Test Details
Ion Selective Electrode (ISE)
Clinical Significance

The ionized calcium is determined by an ion selective electrode methodology. The result that is generated is pH adjusted. The result is empirically based on a measured pH and ionized calcium concentration normalized to a pH of 7.40. This calculation compensates for in vitro changes in pH due to loss of CO2 through specimen handling. 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

Reference Ranges

1.13 – 1.32 mmol/L