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Test Code CAI Calcium, Ionized, Serum

Reporting Name

Calcium, Ionized, S

Useful For

Assessing calcium states during liver transplantation surgery, cardiopulmonary bypass, or any procedure requiring rapid transfusion of whole blood in neonates and critically ill patients


Second-order test in the evaluation of patients with abnormal calcium values

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum SST

Specimen Required

Container/Tube: Serum gel or serum gel microtainer

Specimen Volume: Full tube

Collection Instructions:

1. Allow blood to clot for 30 minutes.

2. Serum gel tube/microtainer must be centrifuged within 1 hour of draw time. Centrifuge with stopper in place for 7 minutes at 3,000 rpm to ensure that the gel barrier separates the serum and cells.

3. Keep specimen anaerobic do not aliquot.

Specimen Minimum Volume

1.75 mL in a 3.5 mL (50% full) in serum gel tube or 1 full serum gel microtainer

Specimen Stability Information

Specimen Type Temperature Time
Serum SST Refrigerated 7 days

Reference Values


≤13 days old: not established

14 days-<1 year: 5.21-5.99 mg/dL

1-<2 years: 5.04-5.84 mg/dL

2-<3 years: 4.87-5.67 mg/dL

3-<24 years: 4.83-5.52 mg/dL

24-≤97 years: 4.57-5.43 mg/dL

≥98 years: not established



≤13 days old: not established

14 days-97 years old: 7.35-7.48

≥98 years old: not established


For SI unit Reference Values, see

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
CAI Calcium, Ionized, S 57333-7


Result ID Test Result Name Result LOINC Value
CAIS Calcium, Ionized, S 57333-7
PHCC pH 2753-2

Method Name

Ion-Selective Electrode (ISE)