Certified Transport Registered Nurse Certification Practice Exam

What percentage of CO2 is transported by hemoglobin?

1. 70%

2. 30%

3. 40%

4. 60%

The correct answer is: 30%

Hemoglobin transports carbon dioxide in two primary forms: physically dissolved in the plasma and chemically bound to hemoglobin as carbamino compounds. While a significant portion of carbon dioxide is indeed carried in the blood, only a minority is transported specifically by hemoglobin. Approximately 20-25% of carbon dioxide is bound to hemoglobin, which aligns closely with the answer of 30%. The remaining carbon dioxide is transported in other forms, predominantly as bicarbonate ions. Thus, stating that 30% of CO2 is transported by hemoglobin provides an understanding of the role hemoglobin plays in gas exchange and highlights the importance of other transport methods for carbon dioxide in the body.