In a CBC, which component is most directly used to evaluate oxygen-carrying capacity?

In a CBC, which component is most directly used to evaluate oxygen-carrying capacity?

• A. Hemoglobin
• B. White blood cells
• C. Platelets
• D. Red blood cell count

Answer: (A)

Oxygen-carrying capacity is determined by how much hemoglobin is present, because hemoglobin is the protein inside red blood cells that binds and transports oxygen. The total hemoglobin concentration in the blood directly reflects how much oxygen can be carried to tissues. Red blood cell count only indicates how many cells are present, but each cell’s hemoglobin content can vary, so a normal cell count might not equal adequate oxygen transport if hemoglobin is low. White blood cells and platelets serve immune and clotting roles, not oxygen transport, so they don’t indicate oxygen-carrying capacity.

Oxygen-carrying capacity is determined by how much hemoglobin is present, because hemoglobin is the protein inside red blood cells that binds and transports oxygen. The total hemoglobin concentration in the blood directly reflects how much oxygen can be carried to tissues. Red blood cell count only indicates how many cells are present, but each cell’s hemoglobin content can vary, so a normal cell count might not equal adequate oxygen transport if hemoglobin is low. White blood cells and platelets serve immune and clotting roles, not oxygen transport, so they don’t indicate oxygen-carrying capacity.