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Arterial Blood Gas (ABG)

PaO₂ (Arterial O₂)

Normal range 80–100 mm Hg (10.6–13.3 kPa SI). Specimen: Arterial blood.

Also known as: partial pressure of oxygen, pO2.

80–100 mm HgCritical: read below

Reference range

Conventionalmm Hg
80100
SIkPa
10.613.3
SpecimenArterial blood
Conventional range80–100 mm Hg
SI range10.6–13.3 kPa
Conversion factor×0.133 (conventional → SI)
Critical value< 40 mm Hg (severe hypoxemia)
PanelArterial Blood Gas (ABG)

Convert any PaO₂ (Arterial O₂) result between units on the unit converter.

What is the normal range for PaO₂ (Arterial O₂)?

The standard teaching reference range for PaO₂ (Arterial O₂) is 80–100 mm Hg in conventional units, or 10.6–13.3 kPa in SI units. This value is measured in arterial blood.

A commonly taught critical (panic) value is < 40 mm Hg (severe hypoxemia). Critical results are reported to the provider immediately under your facility's policy.

Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population — always use the range printed on the actual result.

Above the range

Common causes of a high PaO₂ (Arterial O₂)

  • Supplemental oxygen
  • Hyperventilation

Below the range

Common causes of a low PaO₂ (Arterial O₂)

  • Hypoxemia — pneumonia, ARDS, PE, hypoventilation
  • High altitude

At the bedside

Nursing considerations

  • Reflects oxygenation; correlate with SpO₂ and FiO₂.
  • Falls with age — expect somewhat lower values in older adults.

Study aid

Your notes on PaO₂ (Arterial O₂)

Same panel

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