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Test Code LAB4041 CALCIUM, IONIZED

Important Note

Collect and handle anaerobically. The tube should be filled completely to limit the loss of CO2.

Specimen Type

Preferred Specimen: Lithium Heparin Whole Blood (Dark Green Top)

Alternative Specimen: Serum (SST, Gold, Corvac, Tiger, Red Top Tube) Lithium Heparin Plasma (Mint Green Top, Dark Green Top)

Collection Instructions

Collect and handle anaerobically. The tube should be filled completely to limit the loss of CO2.

Specimen Volume

2 mL

Minimum Volume

1 mL

Turnaround Time

STAT: 1 hour
Routine: 4 hours

Test Schedule

Daily

Sample Stability

Whole blood, unopened: 2 hours Room Temp
 

Separated serum or plasma, unopened:
Room Temp: 8 hours
Refrigerated: 7 days 

Specimen Processing

Spin SST or PST tube within 30 minutes of collection, do NOT remove cap.

Method

ISE

Reference Ranges

Calcium, Ionized mg/dL

          Normal:  4.75 - 5.30

          Critical:  <3..3 - >6.2

 

 

Synonyms

IONIZED CALCIUM

Test Components

Calcium, Ionized, mg/dL;

CPT Codes

82330

Test Limitations

Bedrest for 3 days or more may elevate ionized calcium into the abnormal range. Within the pH range of 7.2-7.6 the normalized calcium value included in the report represents what the ionized calcium concentration would be if the pH of the sample was 7.4 For specimens with pH values outside the 7.2-7.6 range, only the ionized calcium value will be reported since the pH is out of range to calculate the normalized value. This ionized calcium result alone may not reflect the physiologic calcium status due to the pH of the specimen. In rare instances where either the ionized calcium or the pH is beyond the range of the instrument (i.e., ionized calcium 20 mg/dL, and pH < 6.0 or > 8.8), no results will be reported.