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Arterial Blood Gas (ABG)

Arterial pH

Normal range 7.35–7.45 pH units. Specimen: Arterial blood.

Also known as: blood pH, pH.

7.35–7.45 pH unitsCritical: read below

Reference range

ConventionalpH units
7.357.45
SpecimenArterial blood
Conventional range7.35–7.45 pH units
SI range7.35–7.45 pH units
Conversion factor×1 (conventional → SI)
Critical value< 7.20 or > 7.60
PanelArterial Blood Gas (ABG)

Convert any Arterial pH result between units on the unit converter.

What is the normal range for Arterial pH?

The standard teaching reference range for Arterial pH is 7.35–7.45 pH units. This value is measured in arterial blood.

A commonly taught critical (panic) value is < 7.20 or > 7.60. 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 Arterial pH

  • Alkalosis (metabolic or respiratory)

Below the range

Common causes of a low Arterial pH

  • Acidosis (metabolic or respiratory)

At the bedside

Nursing considerations

  • The first value to read in an ABG: < 7.35 acidosis, > 7.45 alkalosis.
  • Then check PaCO₂ and HCO₃⁻ to find the cause and compensation.

Study aid

Your notes on Arterial pH

Same panel

More Arterial Blood Gas (ABG) tests

Base Excess-2–2 mEq/LHCO₃⁻ (Arterial Bicarbonate)22–26 mEq/LPaCO₂ (Arterial CO₂)35–45 mm HgPaO₂ (Arterial O₂)80–100 mm HgSaO₂ (Arterial Oxygen Saturation)95–100 %