I want to help but what do you mean
Reference point .................................
Oxygen is transported in the blood in two ways: A small amount of O 2 (1.5 percent) is carried in the plasma as a dissolved gas. Most oxygen (98.5 percent) carried in the blood is bound to the protein hemoglobin in red blood cells. A fully saturated oxyhemoglobin (HbO 2) has four O 2 molecules attached.
(https://www.cliffsnotes.com/study-guides/anatomy-and-physiology/the-respiratory-system/gas-transport)
