What is the effect of carbon monoxide poisoning on hemoglobin's oxygen-binding capacity?

A It increases the affinity for oxygen
B It decreases the affinity for oxygen
C It has no effect on oxygen binding
D It displaces oxygen from hemoglobin, reducing its oxygen-binding capacity ✓

Explanation

Carbon monoxide poisoning reduces hemoglobin's oxygen-binding capacity by binding to the heme group and displacing oxygen, resulting in a reduced ability to transport oxygen to tissues.

Source

Harrison's Principles of Internal Medicine
Hematology Hematology: Hemoglobin and Oxygen Transport Hematology: Hemoglobin and Oxygen Transport Easy MEDICAL Confidence: high