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Test Code BLOD0656 Calcium, Ionized, Whole Blood, Plasma or Serum

Important Note

DO NOT remove the specimen cap after the blood draw.

Useful For

Determining the “physiologically active” or free calcium level in patients with altered proteins (chronic renal failure, malabsorption, multiple myeloma, and nephrotic syndrome), and in disturbances of acid-base metabolism.


Ion-Selective Electrode (ISE)

Performing Laboratory

Bozeman Health Laboratory Services

Specimen Requirements

Submit only 1 of the following specimens:


Specimen Type: Whole blood

*NOTE: Only draw whole blood sample if specimen can be processed within 1 hour

Container/Tube: Dark-green top (sodium heparin)

Specimen Volume: Full tube

Collection Instructions: 

  1. Keep specimen anaerobic. Do not transfer or uncap tube. 
  2. Send to laboratory within 1 hour.

Specimen Type: Plasma or serum
Container/Tube: Light-green top (lithium heparin gel), green top Microtainer, gold top, or gel Microtainer
Specimen Volume: Full tube
Collection Instructions:

  1. Allow blood to clot for 30 minutes.
  2. Centrifuge with stopper in place for 10 minutes at 3,200 rpm to ensure gel barrier separates serum from cells.
  3. Keep specimen anaerobic. Do not transfer or uncap tube.
  4. Label specimen as plasma or serum.

Specimen Transport Temperature

Whole blood: Ambient <1 hour

Plasma or serum: Refrigerated

Specimen Stability


Specimen Type Temperature Time
Whole blood Ambient 1 hour
Plasma or Serum Refrigerated, anaerobic (capped) 5 days


Reference Values


Age Normal Range Critical Values
0-6 months 1.00-<1.50 mmol/L >1.50 mmol/L
≥ 6 months 1.12-1.32 mmol/L >1.50 mmol/L


Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding