Which blood gas parameter is most affected by the choice of arterial versus venous blood?

Question

Quizplus · Accepted Answer

The parameter most affected by the choice between arterial and venous blood is the partial pressure of oxygen (PO2). Arterial blood is oxygen-rich, coming directly from the lungs, whereas venous blood is oxygen-depleted, having circulated through the body. This results in significantly different PO2 values between arterial and venous samples, with arterial blood having a higher PO2.

Which Blood Gas Parameter Is Most Affected by the Choice