Test Code LAB4041 CALCIUM, IONIZED
Specimen Type
Preferred Specimen: Lithium Heparin Whole Blood (Dark Green Top)
Alternative Specimen: Heparinized Syringe
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: 10 minutes
Routine: 30 minutes
Test Schedule
Daily
Sample Stability
Room Temp: 30 min
On Wet Ice or Refrigerated: 24 Hours
Specimen Processing
Do not place specimen on ice if it will be analyzed within 30 minutes. If specimen cannot be analyzed within 30 minutes, store and transport on ice water.
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.