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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 collection. Centrifuge with stopper in place for 7 minutes at 3000 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 Special Container
Serum SST Refrigerated 7 days SERUM GEL TUBE

Reference Values

IONIZED CALCIUM

≤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

3-23 years: 4.83-5.52 mg/dL

24-97 years: 4.57-5.43 mg/dL

≥98 years: Not established

 

pH

≤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 www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Day(s) Performed

Monday through Sunday

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 US Food and Drug Administration.

CPT Code Information

82330

Clinical Information

Ionized calcium, which accounts for 50% to 55% of total calcium, is the physiologically active form of calcium.

 

Low ionized calcium values are often seen in kidney disease, critically ill patients, or patients receiving rapid transfusion of citrated whole blood or blood products.

 

Increased serum ionized calcium concentrations may be seen with primary hyperparathyroidism, ectopic parathyroid hormone-producing tumors, excess intake of vitamin D, or various malignancies.

 

Nomograms have been used to calculate ionized calcium from total calcium, albumin, and pH values. However, calculated ionized calcium results have proven to be unsatisfactory. A Mayo study of 114 patients found significant differences between ionized and total calcium in 26% of patients.

Report Available

Same day/1 day

Reject Due To

Gross hemolysis Reject
Tubes less than 50% full
Specimens that have been aliquoted, opened, or poorly centrifuged		 Reject

Method Name

Ion-Selective Electrode (ISE)

Disease States

  • Hyperparathyroidism

Forms

If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.