× Test Guide Collection Guides Guidelines News Contact Useful Links

Laboratory Test Reference Guide

Laboratory Information

Test Name


Specimen Collection

Adult Specimen

1.5 mL venous blood in heparinised syringe.

Paediatric Specimen

0.5 mLvenous blood collected into a 1 mL heparinsed blood gas syringe, capped with a filter cap. Remove air immediately after collection by expelling through the filter cap. Mix for 20 seconds. Transport at ambient temperature.

Test Information



Test Availability

Mon - Sun, 24hrs

Laboratory Turnaround Time

30 minutes



Unit of measurement


Reference interval

Venous blood

0 - 6 months:                           2.5 - 3.2 kPa

6 months and older:                3.4 - 4.1 kPa

Arterial blood (not recommended)

Male:                                       3.2 - 3.8 kPa

Female:                                   3.2 - 3.7 kPa

Capillary - not a valid sample type

The reference interval is the same for p50(st) and p50(temp corrected)

Reference interval Attachments

Diagnostic Use Or Instructions

p50 is mainly used to check for haemoglobin variants with high or low oxygen affinity.

See attachment for details

Additional Information

Available on the blood gas analyser in biochemistry.

p50 is a rare request, suggest to inform biochemistry prior to sending a sample for testing.

Contact POCT to arrange testing at the rural laboratories

Minimum Volume

 0.3 mL whole blood collected in to a 1 mL blood gas syringe

Electronic Information

Registration Code