Ideal PaO2 by Age

Estimate expected normal PaO2 based on patient age (sea level, room air).

For educational and clinical reference. Not a substitute for medical judgment. See the medical disclaimer.
Expected PaO2
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References

  1. Sorbini CA, Grassi V, Solinas E, Muiesan G. Arterial oxygen tension in relation to age in healthy subjects. Respiration. 1968;25(1):3-13.

How to use

  1. Enter age in years.
  2. Expected normal PaO2 appears instantly.
  3. Compare to measured arterial blood gas PaO2.

Frequently asked questions

Formula?

Sorbini: PaO2 (mmHg) = 109 − 0.43 × age (years). Approximates expected PaO2 at sea level on room air.

When useful?

For evaluating A–a gradient or whether measured PaO2 is "low for age" in elderly patients.

Limitations?

Approximation. Other formulas exist (e.g., 100.1 − 0.323 × age); discrepancies within ~5 mmHg.

Altitude correction?

Formula is for sea level. Adjust expected PaO2 down at higher altitudes (~3 mmHg per 1000 ft).

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