Hemoglobin: What Your CBC Result Means

Hemoglobin is the iron-containing protein inside red blood cells that binds oxygen in the lungs and releases it to tissue. It is reported on every complete blood count.

It tracks closely with hematocrit, which measures the percentage of your blood volume made up of red cells; hematocrit is usually about three times hemoglobin.

Low hemoglobin is the definition of anemia and commonly explains fatigue, breathlessness on stairs, cold hands, and pale skin. The important question is always why: iron deficiency, blood loss, B12 or folate shortage, inflammation, or kidney disease.

High hemoglobin can reflect dehydration, living at altitude, smoking, sleep apnea, or, less often, a bone marrow condition that needs specialist review.

Building hemoglobin needs iron (red meat, shellfish, lentils, fortified cereals), vitamin B12 (animal foods), folate (leafy greens, beans), and copper. Vitamin C with plant iron improves absorption.

Hydration status, altitude, pregnancy, heavy menstrual periods, recent blood donation, chronic inflammation, and kidney function all shift hemoglobin.