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Laboratory Test Reference Guide

Laboratory Information

Specimen Collection

Specimen Collection and Transport Protocols

Remove at least 3 ml of blood to waste prior to collecting the blood sample from a line.  Transport to the Laboratory within 15 minutes of collection.

Adult Specimen

1.0 mL arterial blood in an adult blood gas syringe. Micro blood gases (venous - capillary) are not appropriate for pO2 or pCO2 estimation.

Paediatric Specimen

0.5 mL blood in a paediatric blood gas syringe. Micro blood gases (venous - capillary) are not appropriate for pO2 or pCO2 estimation.

Sample Delivery to Lab

Ambient temperature, with no air bubbles

Test Information

Department

Biochemistry and POCT

Test Availability

Mon - Sun, 24hrs

Laboratory Turnaround Time

30 minutes

Method

Waikato Hospital Delivery Suite, NICU, Ward E2, ICU, Theatre 2 - ABL800 series; Rural EDs, Waikato Lab, Ward A2, Emergency, HDU, ICU, Ward E5, Theatre 3 - ABL90 Flex

Uncertainty of measurement

pH ±0.003; pCO2± 0.2@ 8.9 kPa or ±0.1 @ 1.5 kPa; pO2 ± 0.3 kPa

Diagnostic Use Or Instructions

Blood gas recommendations:

Do not do blood gases "to get a quick set of electrolytes".

Blood gas analysis is expensive and takes laboratory staff away from other duties and so affects timeliness of other work.

In most cases (including suspected metabolic conditions like DKA, lactic acidosis or bowel ischaemia) a venous blood gas guides management as well as an arterial blood gas.

Arterial blood gas should only be done in selected patients with severe respiratory illness if the result of the arterial pC02 or A-a gradient will aid decision making, and in intubated patients. 

Taking an arterial specimen is much more painful, so don't do an ABG if a VBG will suffice. 

Additional Information

Creatinine is available at Thames only

Minimum Volume

0.3 mL collected into a paediatric blood gas syringe or a full100 µL plastic capillary tube

Electronic Information

Registration Code

BG

HL7 mapping code

$BG