Sign in →

Test Code ICAL or LAB54 Calcium, Ionized, Blood

Important Note

Ionized calcium is sensitive to changes in pH. Exposure to air will cause the CO2 in the sample to evaporate, raising the pH. Therefore, samples should remain capped until testing can be performed.

Prolonged exposure to metabolically active cells will lower the pH. For this reason, specimens should be kept cool after collection, after they are processed, and up until testing can be processed in the lab.

Specimen Requirements

Specimen Type:
  •  Preferred: Whole blood
  • Acceptable: Serum or plasma

 
Container Type:

BMH

Optimal: Mint

Acceptable: Green or Gold

  

 

BBC, BLH or BSH

Optimal: Green

Acceptable: Mint or Gold

  
Optimal Collection Volume: 

5 mL; full tube
Minimum Volume:

1 mL whole blood
Collection Instructions:
  1. Invert several times to mix blood.
  2. Do not centrifuge or remove sample cap.
Specimen Transport:
  • Refrigerated, send as soon as possible
  • Refrigerated samples are stable for 12 hours
  • If sent ambient, samples are stable for 3 hours
Processing Instructions: 
  • Immediately deliver the sample to chemistry.
  • If serum, wait 30 minutes before centrifuging

Specimen Stability

Specimen Type Temperature Time

Whole Blood*

Plasma/Serum

Refrigerated

12 hours

Room Temperature

3 hours

 

*If sample pH falls outside of 7.2-7.6, the non-pH corrected value may be resulted

Specimen Rejection Criteria

  • Inadequately filled tube (< 1 mL)
    • Relatively increased concentration of heparin will falsely lower the ionized calcium result.
  • Samples older than 12 hours refrigerated or 3 hours room temperature at the time of testing

Useful For

Ionized calcium is the physiologically active form of calcium, comprising approximately 45% of the total calcium in plasma. Ionized calcium measurements are useful in the evaluation of renal function and endocrine disorders, during cardiac surgery, and in neonatology.

Methodology

Radiometer - Potentiometric

Reference Ranges

4.5-5.3 mg/dL

 

Critical Values

  • ≤ 3.0 mg/dL
  • ≥ 7.0 mg/dL

Day(s) Performed

24/7

Expected TAT

Same day

Performing Laboratory

Bronson Laboratory, Chemistry - Kalamazoo, Battle Creek, Paw Paw, South Haven 

Sample Retention Time

7 days

CPT Code

82330

LOINC Code

38230-9