sO2 is called oxygen saturation and is defined as the ratio between the concentrations of O2Hb and HHb + O2Hb:
The systematic symbol for arterial blood is sO2(a). The analyzer symbol may be sO2.
What does sO2 tell you?
sO2(a) is the percentage of oxygenated hemoglobin in relation to the amount of hemoglobin capable of carrying oxygen. sO2 allows evaluation of oxygenation and dissociation of oxyhemoglobin as expressed in the ODC.
sO2(a) normal range (adult): 95-99 % (0.95-0.99)
High (normal) sO2:
Sufficient utilization of actual oxygen transport capacity. Potential risk of hyperoxia (see pO2).
Common causes of low sO2:
- Impaired oxygen uptake
- Right shift of ODC
Be aware of the risk of preanalytical errors (air bubbles, storage) on sO2 values.
For more information, go to Preanalytical considerations.