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Test Code LAB5558 Calcium Ionized, Serum

Performing Laboratory

St. Louis Children's Hospital Laboratory  - Core Lab

Specimen Requirements

Patient Preparation: None

Collection Container/Tube:

Preferred: Plain red-top tube

Acceptable: Gold top SST tube

Submission Container/Tube: For uncentrifuged specimen, forward at ambient temperature. Specimen must be received in the laboratory within 2 hours of draw. DO NOT remove tube top.
For centrifuged specimen on gel, forward at ambient temperature. Specimen must be received in the laboratory within 24 hours of draw. DO NOT remove tube top.

Specimen Collection Volume: 1.0 mL (minimum 0.5 mL)

Special Instructions: Mix well and send to lab immediately. 

 

Sample Rejection

Mislabled or unlabeled specimens 

Specimens collected in Mint Green-top LiHep tubes or microtainers

Logistics

Test Availability: Monday-Sunday

Cut-off time: None, performed as received

Turnaround Time: Same Day; 30 minutes from receipt in perfoming lab

Reference Values

Reference Interval: 

< 24 hours: 4.50-5.75 mg/dL                                                 
24 hours - 4 days: 4.15-5.40 mg/dL
4 days - 6 months: 4.85-5.80 mg/dL
6 - 30 months: 4.60-5.50 mg/dL
30 months - 18 years: 4.45-5.25 mg/dL
≥ 18 years: 4.50-5.10 mg/dL

Critical Value: 

All ages:  <2.60  OR  >6.80 mg/dL                                                            

Critical test results will be called back automatically initially and every 24 hours thereafter.

 

Methodology

Ion-Selective Electrode (ISE)

Limitations

  • NA

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: Spin to separate cells from serum giving tube to Blood Gas bench

Processed Volume: 1.0 (minimum 0.3 mL) 

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 30 minutes
Plasma/Serum (processed) Refrigerated        
  Ambient  4 hours
  Frozen  not acceptable   

 

Test Classification and CPT Code

82330

LOINC

12180-6

Last Reviewed

10/2025