According to Amperor Direct, in healthy people, normal SpO2, or blood oxygen saturation levels, should range from 94 to 99 percent. For a person with a mild respiratory disease, the value should be at least 90 percent.
Oxygen saturation is the ratio of oxyhemoglobin to the total concentration of hemoglobin in the blood. Hemoglobin transports oxygen from the lungs to other parts of the body. It is an iron-containing protein bound to red blood cells, notes Amperor Direct. Oxyhemoglobin is hemoglobin that is a combination of hemoglobin and oxygen from the lungs. SpO2 values are obtained with the use of pulse oximetry, a noninvasive method to measure arterial blood oxygen saturation and pulse rate.