Here are some general guidelines to understanding oximeter readings and SpO2 values. A normal healthy person should be able to achieve normal blood oxygen saturation levels (SpO2) of 94% to 99%. For patients with mild respiratory diseases, the SpO2 should be 90% or above. Hypoxemia is a below-normal level of oxygen in your blood, specifically in the arteries. … Values under 60 mm Hg usually indicate the need for supplemental oxygen. Normal pulse oximeter readings usually range from 95 to 100 percent. Values under 90 percent are considered low.