Standard hemoglobin oxygen saturation levels

Steps:

• At lungs, high PO2 (~100 mmHg) fully saturates hemoglobin per oxygen dissociation curve.
• Typical lung saturation is 94-98% under normal conditions.
• In metabolically active tissues, low PO2 (~20-30 mmHg) and factors like Bohr shift reduce saturation.
• Standard value for active tissues is ~46%, reflecting oxygen unloading for metabolism.

Why C is correct:

• Matches physiological norms: 94% arterial saturation in lungs and 46% in active tissues, as per oxygen-hemoglobin dissociation curve data.

Why the others are wrong:

• A: Underestimates lung saturation (82% too low) and tissue value inconsistent with active metabolism.
• B: Lung value (92%) slightly low; tissue (46%) correct but pair mismatches standards.
• D: Tissue saturation (66%) too high for active sites, implying insufficient oxygen delivery.

Final answer: C