An interlaboratory study of blood-gas analysis: dependence of pO2 and pCO2 results on atmospheric pressure.

Blood-gas data from a large interlaboratory survey were analyzed to determine whether pO2 and pCO2 results are affected by the atmospheric pressure at the measuring location. A small but statistically significant dependence was found, averaging about 2.3% per 100 mmHg (1.7% per 10 kPa) for pO2 and 1.0% per 100 mmHg (0.75% per 10 kPa) for pCO2.