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Test Code LAB54 Calcium, Ionized, Serum

Additional Codes

Mayo Test Code: CAI

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

Method Name

Ion-Selective Electrode (ISE)

Performing Laboratory

Mayo Medical 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

Reject Due To


Mild OK; Gross reject






Tubes less than 50% full; Specimens that have been aliquoted, opened, or poorly centrifuged.


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

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 17864-0
PHCC pH 2753-2

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.

Secondary ID