Blood gas results from a seemingly healthy patient reveal pH 7.37, PaCO2 15 torr, PaO2 140 torr on room air. Which conclusion is most appropriate?

• A. A venous blood sample was drawn
• B. The blood gas sample was not cooled prior to analysis
• C. The blood gas sample had an air bubble in it
• D. The patient's blood gas sample was mixed up with another sample

Answer: (C)