oxygen capacity of blood, the maximum amount of oxygen that can combine chemically with a given amount of hemoglobin in blood. It does not include oxygen dissolved in plasma. Although 1 g of hemoglobin theoretically can bind a maximum of 1.34 mL of oxygen at standard temperature and pressure, this value is never actually achieved in vivo because of factors such as the formation of carboxyhemoglobin and the presence of methemoglobin or other inactive hemoglobins.
