For a 1-month-old to an adult, normal venous pO2 levels range from 25 to 29 millimeters of mercury. PO2 is one of several blood gases that are measured to evaluate lung function and the acid-versus-base balance.
Abnormal values for blood gases indicate a person is not exchanging oxygen and carbon dioxide properly. Blood gas tests are ordered when there are problems such as difficulty breathing, chronic obstructive pulmonary disease or asthma. Conditions that may indicate an acid/base imbalance include heart failure, kidney failure, infections, diabetes and drug overdose. Along with electrolyte tests, blood gas tests are ordered to evaluate organ function when these conditions are present.