Which of the following is considered a normal value for arterial oxygen saturation?

• A. 85-95%
• B. 90-95%
• C. 95-100%
• D. 100-105%

Answer: (C)

Arterial oxygen saturation, commonly measured by pulse oximetry, indicates the percentage of hemoglobin binding sites in the bloodstream occupied by oxygen. A normal arterial oxygen saturation level typically ranges from 95% to 100%. This range is essential for ensuring that tissues and organs receive adequate oxygen for metabolism.

Values below 95% can indicate possible hypoxemia, which can lead to various pathological states if oxygen delivery is compromised. Conversely, saturation levels above 100% are physiologically impossible since hemoglobin can only be fully saturated up to a maximum of 100%. Thus, the correct range for normal arterial oxygen saturation reflects the upper and lower bounds of effective oxygen transport within the body.