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22397 Calcium, Ionized, Blood

Calcium, Ionized, Blood
Test Code: IC
Synonyms/Keywords
IC, Ionized Calcium, Free Calcium​, i-Stat Ionized Calcium
Useful For
It is useful in evaluation of renal function and endocrine disorders, during cardiac surgery, and in neonatology.​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​
Whole Blood 
Low- or balanced-Heparin Blood Gas syringe
For Newborns;  balanced-Heparin capillary tube Full syringe or capillary tube Full syringe or capillary tube
​No ​Whole Blood ​Serum Separator Tube (SST) ​Red Top Tube (RTT) ​5 to 10 mL tube filled completely ​5 to 10 mL tube filled completely
​No ​Serum ​Serum Separator Tube (SST) or Red Top Tube (RTT) ​Full aliquot, amount depends on size of the container ​​Full aliquot, amount depends on size of the container
Collection Processing Instructions
Marshfield Center: Collect specimen anaerobically in a 5-7 mL SST or RTT completely filled.  DO NOT REMOVE CAP FROM THE TUBE. Alternatively, heparinized whole blood, either venous or aterial, collected anaerobically in a low- or balanced-heparin blood gas syringe.
 
Surgery patients:  Whole blood without anticoagulant is acceptable from pre-heparinized heart surgery patients, collected in a syringe devoid of any externally added heparin.
 
Newborns:  Preferred specimen is a balanced-heparin capillary tube.  Other types of capillary tubes or collection containers are unacceptable.  Transport to laboratory within 30 minutes of collection, preferred transport is on ice-pack.  
 
All Other Facilities:  Collect specimen anaerobically in a 5 to 10 mL SST tube, filled completely, and centrifuged within 4 hours of collection.  (Centrifuged SST samples are preferred in case other tests are requested, but not required).  Alternatively, specimens collected anaerobically in a 5 to 10mL un-centrifuged RTT are also acceptable, but less desirable.  DO NOT REMOVE CAP FROM THE TUBE.  
 
For pediatric samples where a dedicated red top is not feasible due to excessive sample volume, draw red top tube and following centrifugation, remove serum and rapidly transfer to a small polypropylene tube (i.e. Sarstedt) aliquot container, FILLING THE CONTAINER IN ITS ENTIRETY (to avoid any air exchange). Cap the filled container immediately and store refrigerated prior to and during transport. It may also be frozen for transport.
Specimen Stability Information
Specimen Type Temperature Time
Whole Blood - Syringe​  ​ ​Refrigerate ​ ​4 hours​
​Ambient​ 30 minutes
Whole Blood - SST/RTT Refrigerate 70 hours​
Ambient​ 6 hours​
Serum​​ ​ Frozen ​ 45 days
​Refrigerate ​ ​7 days
Rejection Criteria
Specimens exposed to air
Plasma separator tubes​
Other syringes than those listed​
​Capillary tubes other than balanced-heparin 
​Gross hemolysis
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Bloomer​ ​​Monday through Friday ​Less than 2 hours​ ​Ion-Selective Electrode Potentiometry/i-STAT
​Cadott ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Chetek ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Colby/Abbotsford ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Cornell ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Cumberland ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
Diagnostic Treatment Center ​Monday through Sunday​ ​Less than 2 hours​ ​Radiometer
​Eagle River​ ​Monday through Friday ​Less than 2 hours ​​​Ion-Selective Electrode Potentiometry/i-STAT
​Eau Claire ​​Monday through Sunday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
Flambeau Hospital​ ​Monday through Sunday​ ​Less than 2 hours​ ​Reference Electrode/Gem 4000
Hayward​ ​​​Monday through Friday ​​Less than 2 hours​ ​​​Ion-Selective Electrode Potentiometry/i-STAT
Marshfield​ Monday through Sunday​ Less than 2 hours​ Roche Cobas b221
​Mercer ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Mosinee ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Oakwood ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
Phillips​ ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Rhinelander ​Monday through Friday ​Less than 2 hours ​​​Ion-Selective Electrode Potentiometry/i-STAT
​Stettin ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Wittenberg ​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
Test Information
​Analysis does not include a total calcium. The total calcium must be ordered as a separate test if needed.
When determining ionized calcium for diagnosis of a disorder in Ca metabolism, a four hour fasting sample is recommended.
Reference Range Information
Performing Location Reference Range
All Performing Sites 0-4 days: 4.3-5.5 mg/dL
5-30 days: 4.8-6.0 mg/dL
1 mo.-19 yrs.: 4.9-5.5 mg/dL
>=20 yrs.: 4.5-5.3 mg/dL ​

See Critical Value List for list of current critical values

Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
82330 ​
Synonyms/Keywords
IC, Ionized Calcium, Free Calcium​, i-Stat Ionized Calcium
Ordering Applications
Ordering Application Description
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​
Whole Blood 
Low- or balanced-Heparin Blood Gas syringe
For Newborns;  balanced-Heparin capillary tube Full syringe or capillary tube Full syringe or capillary tube
​No ​Whole Blood ​Serum Separator Tube (SST) ​Red Top Tube (RTT) ​5 to 10 mL tube filled completely ​5 to 10 mL tube filled completely
​No ​Serum ​Serum Separator Tube (SST) or Red Top Tube (RTT) ​Full aliquot, amount depends on size of the container ​​Full aliquot, amount depends on size of the container
Collection Processing
Marshfield Center: Collect specimen anaerobically in a 5-7 mL SST or RTT completely filled.  DO NOT REMOVE CAP FROM THE TUBE. Alternatively, heparinized whole blood, either venous or aterial, collected anaerobically in a low- or balanced-heparin blood gas syringe.
 
Surgery patients:  Whole blood without anticoagulant is acceptable from pre-heparinized heart surgery patients, collected in a syringe devoid of any externally added heparin.
 
Newborns:  Preferred specimen is a balanced-heparin capillary tube.  Other types of capillary tubes or collection containers are unacceptable.  Transport to laboratory within 30 minutes of collection, preferred transport is on ice-pack.  
 
All Other Facilities:  Collect specimen anaerobically in a 5 to 10 mL SST tube, filled completely, and centrifuged within 4 hours of collection.  (Centrifuged SST samples are preferred in case other tests are requested, but not required).  Alternatively, specimens collected anaerobically in a 5 to 10mL un-centrifuged RTT are also acceptable, but less desirable.  DO NOT REMOVE CAP FROM THE TUBE.  
 
For pediatric samples where a dedicated red top is not feasible due to excessive sample volume, draw red top tube and following centrifugation, remove serum and rapidly transfer to a small polypropylene tube (i.e. Sarstedt) aliquot container, FILLING THE CONTAINER IN ITS ENTIRETY (to avoid any air exchange). Cap the filled container immediately and store refrigerated prior to and during transport. It may also be frozen for transport.
Specimen Stability Information
Specimen Type Temperature Time
Whole Blood - Syringe​  ​ ​Refrigerate ​ ​4 hours​
​Ambient​ 30 minutes
Whole Blood - SST/RTT Refrigerate 70 hours​
Ambient​ 6 hours​
Serum​​ ​ Frozen ​ 45 days
​Refrigerate ​ ​7 days
Rejection Criteria
Specimens exposed to air
Plasma separator tubes​
Other syringes than those listed​
​Capillary tubes other than balanced-heparin 
​Gross hemolysis
Useful For
It is useful in evaluation of renal function and endocrine disorders, during cardiac surgery, and in neonatology.​
Reference Range Information
Performing Location Reference Range
All Performing Sites 0-4 days: 4.3-5.5 mg/dL
5-30 days: 4.8-6.0 mg/dL
1 mo.-19 yrs.: 4.9-5.5 mg/dL
>=20 yrs.: 4.5-5.3 mg/dL ​

See Critical Value List for list of current critical values

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Bloomer​ ​​Monday through Friday ​Less than 2 hours​ ​Ion-Selective Electrode Potentiometry/i-STAT
​Cadott ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Chetek ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Colby/Abbotsford ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Cornell ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Cumberland ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
Diagnostic Treatment Center ​Monday through Sunday​ ​Less than 2 hours​ ​Radiometer
​Eagle River​ ​Monday through Friday ​Less than 2 hours ​​​Ion-Selective Electrode Potentiometry/i-STAT
​Eau Claire ​​Monday through Sunday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
Flambeau Hospital​ ​Monday through Sunday​ ​Less than 2 hours​ ​Reference Electrode/Gem 4000
Hayward​ ​​​Monday through Friday ​​Less than 2 hours​ ​​​Ion-Selective Electrode Potentiometry/i-STAT
Marshfield​ Monday through Sunday​ Less than 2 hours​ Roche Cobas b221
​Mercer ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Mosinee ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Oakwood ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
Phillips​ ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Rhinelander ​Monday through Friday ​Less than 2 hours ​​​Ion-Selective Electrode Potentiometry/i-STAT
​Stettin ​​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
​Wittenberg ​Monday through Friday ​Less than 2 hours​ ​​Ion-Selective Electrode Potentiometry/i-STAT
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
82330 ​
For most current information refer to the Marshfield Laboratory online reference manual.