Calcium, Ionized, Serum/Plasma

Sunquest Code:ICA  
Epic Code:LAB54Epic Name:Calcium Ionized
Order Instructions:Order ICAW for whole blood and ICA for plasma/serum.
Synonyms:Ionized Calcium
Methodology:Ion selective electrode
Turnaround Time:Performed and reported 24 hours/day.

Collection Instructions

Optimal Volume:1 mL
Minimum\Peds Volume:0.5 mL
Container:Green (lithium heparin) on ICE (Green (lithium heparin, gel), Red or gold (gel))
Collection Instructions:


  • Do not remove stopper.
  • Place sample on ice and deliver to laboratory for processing within 1 hour of collection.
  • Acceptable without ice if received within 30 minutes of collection.
  • If unprocessed samples cannot be delivered to the laboratory within 1 hour of collection, a whole blood ionized calcium testing should be requested. Whole blood samples are stable on ice for 4 hours.
Causes for Rejection:Sample exposed to air during collection or transport not analyzed within 1 hour of collection, specimen on ice not received within 1 hour of collection, room temperature specimen not processed within 30 minutes of collection.

Processing and Shipping

Specimen Processing:
Centrifuge with stopper in place within one hour of collection. Do not open the tube or split the sample. Store in refrigerator.

If collected in a red top (plain) tube, allow the sample to clot for 15 minutes before centrifuging; do not remove stopper.
Whole blood specimens collected on ice and maintained anaerobically may be analyzed within 4 hours using test code ICAW. SI Unit Conversion Factors: mg/dl x 2.5 = mmol/L. See ICAW.
Shipping Instructions:Ship unopened (anaerobically) at refrigerated temperature.
Stability:Centrifuged, refrigerated specimens are acceptable for 7 days if stopper is not removed. Specimens that have been exposed to air should be analyzed within 1 hour if pH is 7.35-7.45; otherwise recollect. Whole blood samples on ice are stable for 4 hours. See ICAW.
Test Performed at or Referral Lab Chemistry  (UMMC-East Bank, Fairview Lakes - FLMC, Fairview Ridges - FRH, Fairview Northland - FNMC, Fairview Southdale - FSH, UMMC/UMMCH-West Bank, UMMC NICU, M Health Clinic and Surgery Center)


Critical Range:0-11 mo: Less than 3.5 mg/dL and greater than 7.0 mg/dL; 1 y & older: Less than 3.0 mg/dL and greater than 7.0 mg/dL
Reference Range:0-11 mo: 5.1-6.3 mg/dL; 1 year and older: 4.4-5.2 mg/dL


1)       Suspect hypocalcemia or hypercalcemia.

2)       Monitor treatment for calcemic disorder.


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