Bicarbonate, blood gas

Diagnostic Use

Determination of bicarbonate is an important part of blood-gas analysis.

Bicarbonate is calculated from pH and pCO₂ using the Henderson–Hasselbalch equation

Department

Core Biochemistry

Delphic Registration Code

BGS

Synonyms

HCO3, blood gas

Turnaround Time

60 minutes

Test Code

3504

Specimen Type

• Whole Blood

Specimen Requirements

Tube/Container Type:

Preferred

• Syringe

Acceptable

• Lithium Heparin - Non-gel (Green Cap)

Preferred Sample Volume (ml)

5.0

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• Syringe

Preferred Sample Volume (ml)

0.3

Pre-testing Requirements

In order to obtain an accurate result the specimen must be maintained in an anaerobic state. Exposure to air will cause the bicarbonate concentration of the specimen to decrease.

Additional Specimen Information

Register sample as pH/BGAS to avoid sample being centrifuged in error
Treat as urgent.
Patient sample:
Blood 5 mL (or full tube) heparinised (T34) taken directly, or 0.5 mL whole blood in heparinised syringe.

Aliquot Instructions

Sample Type

• Whole Blood

Transport to Lab

Chilled (2 - 8 degrees Celsius)

Additional Referral/Aliquot Information

Sample aliquot:
Blood tube unopened sent to the Core Biochemistry Lab, or 0.5 mL whole blood.
Transport on ice, within 15 mins, sample must be kept anaerobic

Interpretation

The bicarbonate result should be interpreted in the context of the overall blood gas profile.

A low bicarbonate may represent a metabolic acidosis or metabolic compensation for a chronic respiratory alkalosis.

A high bicarbonate may represent a metabolic alkalosis or metabolic compensation for chronic respiratory acidosis.

Reference Intervals

Test Method

Calculated from pH & PCO₂ on blood gas analyser.

Non-Funded Test Cost

$24.50 (Exclusive of GST)

Billing Code

3002

Contact Information

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