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Arterial blood gases (ABGs), venous blood gases, capillary blood gases, cord blood gases.

Common Use:
To assess oxygenation and acid base balance.

Whole blood. Specimen volume and collection container may vary with collection method. See Intratest section for specific collection instructions. Specimen should be tightly capped and transported in an ice slurry.

Normal Findings:
(Method: Selective electrodes for pH, Pco2 and Po2)

Blood Gas Value (pH)ArterialVenousCapillary
Birth, cord, full term7.11–7.367.25–7.457.32–7.49
Note: SI units (conversion factor × 1).
Pco2ArterialSI Units (conventional units × 0.133)VenousSI Units (conventional units × 0.133)CapillarySI Units (conventional units × 0.133)
Scalp40–50 mm Hg5.3–6.6 kPa
Birth, cord, full term32–66 mm Hg4.3–8.8 kPa27–49 mm Hg3.6–6.5 kPa
Newborn–adult35–45 mm Hg4.7–6 kPa41–51 mm Hg5.4–6.8 kPa26–41 mm Hg3.5–5.4 kPa
Po2ArterialSI Units (conventional units × 0.133)VenousSI Units (conventional units × 0.133)CapillarySI Units (conventional units × 0.133)
Scalp20–30 mm Hg2.7–4 kPa
Birth, cord, full term8–24 mm Hg1.1–3.2 kPa17–41 mm Hg2.3–5.4 kPa
0–1 hr33–85 mm Hg4.4–11.3 kPa
Greater than 1 hr–adult80–95 mm Hg10.6–12.6 kPa20–49 mm Hg2.7–6.5 kPa80–95 mm Hg10.6–12.6 kPa
HCO3Arterial Conventional & SI UnitsVenous Conventional & SI UnitsCapillary Conventional & SI Units
Birth, cord, full term17–24 mmol/L17–24 mmol/L
2 mo–2 yr16–23 mmol/L24–28 mmol/L18–23 mmol/L
Adult22–26 mmol/L24–28 mmol/L18–23 mmol/L
O2 SatArterialVenousCapillary
Birth, cord, full term40%–90%40%–70%
Values may be at the lower end of the normal range in older adults
Oxygen Content: ArterialOxygen Content: Venous
6.6–9.7 mmol/L 4.9–7.1 mmol/L
Tco2Arterial Conventional & SI Units mmol/LVenous Conventional & SI Units mmol/L
Birth, cord, full term13–22 mmol/L14–22 mmol/L
Adult/child22–29 mmol/L25–30 mmol/L
Base Excess ArterialConventional & SI Units
Birth, cord, full term(–10) – (–2) mmol/L
Adult/child(–2) – (+3) mmol/L

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