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Blood Gas, Arterial

Includes: pH, pCO2, pO2, Bicarbonate, Base Balance, O2 Sat. (measured), Oxyhemoglobin, Carboxyhemoglobin, Methemoglobin

Specimen Type = blood syringe

Specimen Type

Test ID LAB76
EPIC Order BLOOD GAS, ARTERIAL
CPT Code(s) 82805, 84311, 83050, 82375
Group/Individual Test Group
Laboratory Core Laboratory-Blood Gas
Tube Station 31
Specimen Routine: 1.5 mL whole blood in 3cc syringe w/lyophilized heparin in BG Kit or SafePICO Collection Kit. PLEASE SPECIFY source. See Comments
Micro: 0.5 mL whole blood in 1cc syringe w/lyophilized heparin in BG Kit or full heparinized capillary tube. PLEASE SPECIFY source. See Comments
Stability
Room Temp/Refrigerated: 30 minutes
Frozen: NO
Availability Routine: 24 Hours/Day
STAT: Yes
Turnaround Time 10 minutes
Reference Range Normal: See Table below
Critical: See Table below
Comments
  • Blood collection tubes are not acceptable.
  • Deliver Immediately to Blood Gas lab. The time between specimen collection and analysis should not exceed 30 minutes.
  • Syringes with needles attached will NOT be accepted.
  • Blood Gas syringes may be obtained from Central Distribution.
  • Heparinized, anaerobic technique. Heparinized capillary samples can be analyzed if at least 200 µL of clot-free blood is present.
  • If temperature-corrected results are required, see test LAB5301 (Blood Gas, Arterial Temperature Corrected).
  • Oxygen Saturation is a measure of the fraction of oxygenated hemoglobin in relation to the amount of hemoglobin capable of transporting oxygen. Oxygen Saturation can be clinically misleading in the presence of dyshemoglobins such as carboxyhemoglobin and methemoglobin. This is because the oxygen-carrying capacity of the blood will be decreased but the saturation will often remain within reference limits.
  • Oxyhemoglobin represents the fraction of oxygenated hemoglobin in relation to the total hemoglobin present, including non-oxygen-binding hemoglobins. In healthy individuals, oxyhemoglobin and oxygen saturation are approximately equal. In the presence of dyshemoglobins, oxyhemoglobin can be considerably lower than oxygen saturation. Although the oxygen saturation often remains within the reference limits, the oxygen-carrying capacity of the blood may be severely decreased.
Reference Range Critical Range
pH 7.35-7.45 <7.20 or >7.65
pCO2 35-45 mmHg <20 or >65 mmHg
pO2 80-110 mmHg (at Room Air) <40 mmHg (arterial)
HCO3 22-27 mmol/L N/A
Base Bal ±2 mmol/L N/A
O2 Sat 94-100% <75%
O2 Hb 94-100% <75%
Met Hb <1.5% >10%
CO Hb Nonsmokers=<1.2%
Smokers 1-2 packs/day=4.0-5.0%
Smokers >2 packs/day=6.0-8.0%		 >20%

Reviewed by J. Carr on January 15, 2026

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514