Which lab value is most directly used to assess oxygen-carrying capacity of blood?

Which lab value is most directly used to assess oxygen-carrying capacity of blood?

• A. Hemoglobin
• B. WBC count
• C. Platelet count
• D. Sodium

Answer: (A)

Oxygen-carrying capacity hinges on how much hemoglobin is available to bind and transport oxygen. Hemoglobin is the protein inside red blood cells that grabs oxygen in the lungs and releases it to tissues throughout the body; the concentration of hemoglobin per unit volume directly determines how much oxygen can be carried. The other labs listed don’t reflect oxygen transport—white blood cell count and platelet count relate to immune function and clotting, while sodium is an electrolyte involved in fluid and nerve/muscle function. So measuring hemoglobin provides the most direct assessment of how much oxygen the blood can carry.

Oxygen-carrying capacity hinges on how much hemoglobin is available to bind and transport oxygen. Hemoglobin is the protein inside red blood cells that grabs oxygen in the lungs and releases it to tissues throughout the body; the concentration of hemoglobin per unit volume directly determines how much oxygen can be carried. The other labs listed don’t reflect oxygen transport—white blood cell count and platelet count relate to immune function and clotting, while sodium is an electrolyte involved in fluid and nerve/muscle function. So measuring hemoglobin provides the most direct assessment of how much oxygen the blood can carry.