Calcium, Ionised (Blood)

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Testing Laboratory

Auckland Te Toka Tumai | Auckland Hospital

Department

Chemical Pathology

Delphic Registration Code (Alpha Code)

ICA

Test Code (Numeric Code)

0334

Laboratory Handling

Phlebotomy

Preferred sample:
- Siemens 1.0 mL (vented/self-fill) and non-vented (aspirator) blood gas syringes.
- The amount of heparin is exactly calibrated to not interfere with analysis of electrolytes, ionised calcium or glucose.
- The recommended fill volume is 0.6 mL, but a minimum volume of 0.3 mL of blood can be analysed with no apparent effect on the results.
- Put patient label on the barrel of syringe, not the plunger.

Alternatively:
- A FULL plain (red-top) tube of blood with minimum air space above is acceptable, if it sent to the laboratory without delay.

Transport

Send Urgently to Laboratory.
External Referrers: Collect in SST tube, which must be at least 80% full, allow to clot for 30 minutes and centrifuge within 1 hour of collection, do not open the tube or aliquot.

Laboratory

Ionised Calcium Urgent test!
- Centrifuge within 1 hour of collection.
- Code barcode ICA
- Do not separate or open.
- Do not put on 8100, hand deliver to automation staff with copy of the form.

Sample Stability

-

Associated Tests

Synonyms

Calcium - plasma free, free calcium, Ionised calcium, iCa, fCa

Turnaround Time

3 hours

Please do not use the abbreviation ICA when requesting this test - the request may be confused with Islet Cell Antibodies.

Specimen Type

  • Whole Blood

Specimen Requirements

Tube/Container Type:

Preferred
  • Blood Gas Syringe
Acceptable
  • Plain (Red Top)
  • SST II (Gold Cap)
Preferred Sample Volume (ml)

5

Minimum Sample Volume (ml)

3

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred
  • SST II (Gold Cap)
Preferred Sample Volume (ml)

1

Minimum Sample Volume (ml)

1

Additional Specimen Information

Adults: Preferred: Siemens 1.0 mL (vented/self-fill) and non-vented (aspirator) blood gas syringes, or full SST or plain Blood tube.
Paediatrics: 0.5 mL Paediatric Microtainer SST Blood (x2).

Last updated: 26/08/2026